Product Overview: What Is radius HP-C28BT?
radius HP-C28BT is a pair of true wireless earbuds from radius Co., Ltd.
Its most distinctive feature is the cat-shaped charging case. Instead of looking like a typical tech accessory, the case is designed to feel like a small cat-themed item you can keep on a desk, shelf, or bedside table.
As an audio product, HP-C28BT is a Bluetooth in-ear true wireless earbud model with music playback, calling, low-latency gaming mode, water resistance, and USB Type-C charging.
This article does not treat HP-C28BT as a pet robot. It reviews HP-C28BT as a cat-themed gadget, then compares it with Mia, another cat-themed product, to clarify the difference between a cute everyday audio accessory and a talking AI cat companion robot.


Key Takeaways
What HP-C28BT Offers
- True wireless earbuds with a cat-shaped charging case
- A product in radius's NEKO true wireless earphones line
- Bluetooth 5.3, low-latency gaming mode, and IPX4 water resistance
- Up to about 3.5 hours of playback on the earbuds, and up to about 17.5 hours with the charging case
Strengths
- The cat motif is clear and gift-friendly
- The case works well as a cute desk or everyday carry item
- The official product page shows a price of 8,980 yen including tax
- Amazon reviews indicate that some buyers value both the cute appearance and the sound quality
Points to Watch
- HP-C28BT is an earbud product, not a talking robot like Mia
- It does not offer conversation, reminders, weather updates, family messages, or companionship features
- The standalone earbud battery life is modest compared with some long-battery models
- The cat experience is mainly visual and product-design-based, not interactive like a pet robot
Who It May Suit
- People who like cat-themed earbuds or accessories
- Users looking for cute true wireless earbuds
- People choosing a small gift for a cat lover
- Buyers who want a practical cat-themed gadget rather than a robot companion
Quick Verdict
HP-C28BT is best for people who want cute cat-themed earbuds they can use every day.
The sleeping-cat-style charging case is memorable and easy to recommend as a gift for cat lovers. At the same time, HP-C28BT does not talk to you, show expressions, remind you about events, or provide weather updates.
If you want a cat-themed audio accessory, HP-C28BT is worth considering. If you want a small cat-shaped presence that talks and offers daily voice interactions, Mia belongs in a different category.
Video note: no official YouTube demo was confirmed for this review.
Price and How to Buy
Price
The official radius page lists HP-C28BT at 8,980 yen including tax.
Prices may vary by store, color, stock status, and campaign timing. Before buying, check the latest official store or marketplace listing.
Where to Check
You can check the official product information here:

An Amazon Japan product page for the HP-C28BT series is also available:
Buying Cautions
- Stock and prices may differ by color or model.
- On Amazon, check whether reviews refer to the same color and model you plan to buy.
- As with all in-ear true wireless earbuds, comfort and fit depend on ear shape.
Main Features and Everyday Use
HP-C28BT is designed for music, calls, videos, and casual gaming audio. The cat-shaped case makes it feel more personal than a standard earbud case, but the core function is still everyday audio playback.

Main Features
- Bluetooth 5.3
- In-ear true wireless design
- Low-latency gaming mode
- IPX4 water resistance
- USB Type-C charging
- Up to about 3.5 hours of playback on the earbuds
- Up to about 17.5 hours of playback with the charging case
- Calling support
- Cat-shaped charging case
Usage and Demo
No official YouTube demo was confirmed for this article.
Future Updates
No specific future update information was confirmed.
FAQ
Quick Summary
- Price: the official page lists 8,980 yen including tax.
- What it does: music playback, calls, low-latency gaming mode, and everyday wireless earbud use.
- Main caution: it is a cat-designed earbud product, not a conversation robot or pet robot.
Is HP-C28BT a pet robot?
No. HP-C28BT is a pair of true wireless earbuds.
The charging case looks like a small cat, but the product does not talk to you, change expressions, or support daily companionship features.
Is it easy to use?
Amazon reviews suggest that some buyers appreciate the cute look and sound quality. However, fit, touch controls, and comfort vary by user.
Before buying, check whether the earbud shape is likely to suit your ears and whether the playback time fits your daily use.
Is the size or weight a concern?
The official page lists each earbud at about 4g, and about 34g including the charging case.
That makes it easy to carry as a typical true wireless earbud product. The cat-shaped case adds charm without turning it into a large gadget.
How should I think about battery life?
The official page lists up to about 3.5 hours of playback on the earbuds and up to about 17.5 hours with the charging case.

For commuting or short daily use, that may be enough. For long travel days or all-day use, you should expect to return the earbuds to the case for charging.
Specs Summary
| Item | Details |
|---|---|
| Product name | HP-C28BT |
| Manufacturer | radius Co., Ltd. |
| Product category | True wireless earbuds |
| Price | 8,980 yen including tax on the official page |
| Bluetooth | Bluetooth 5.3 |
| Form factor | In-ear true wireless earbuds |
| Playback time | Up to about 3.5 hours on earbuds, up to about 17.5 hours with case |
| Charging port | USB Type-C |
| Water resistance | IPX4 |
| Low-latency mode | Supported |
| Main uses | Music, calls, videos, casual game audio |
| Target age | Not confirmed from official information |
| Conversation features | No companion conversation; calling microphone is included |
| App integration | Not confirmed from official information |
| Monthly fee | Not confirmed from official information |
Reviews and User Feedback
Amazon Japan has a product page and customer reviews for the HP-C28BT series. Checked on June 30, 2026.
Because Amazon pages can group colors and variants, confirm whether each review refers to the exact model you plan to buy.
Positive Review Notes
Cute appearance
The cat-shaped case is one of the main reasons to choose HP-C28BT. It is not just an audio product; it is also a small cat-themed item that buyers may enjoy seeing and carrying.
Some Amazon review comments also refer positively to sound quality. That matters because HP-C28BT needs to work as everyday earbuds, not only as a cute object.
Improvement Points
A short, specific low-rating review suitable for quotation was not sufficiently confirmed.
The main caution is not a single quoted complaint, but the nature of true wireless earbuds in general. Fit, touch control preferences, call quality, connection stability, and battery expectations can vary from person to person.
Buying Checks From Reviews
- Choose it if the cat-shaped case is a major appeal.
- Check whether about 3.5 hours of standalone playback is enough.
- Confirm return conditions if you are sensitive to earbud fit.
- Do not buy it expecting cat-robot-style conversation or reactions.
Overall Evaluation
HP-C28BT combines cat-themed product design with the basic functions of true wireless earbuds.
It is easy to understand as a gift for cat lovers, but its category is audio. Its sense of comfort comes from cuteness, daily carry value, and the visual charm of the case, not from robot-like interaction.
If you want a cat-themed gadget, HP-C28BT makes sense. If you want a small cat-shaped presence that talks, gives reminders, and feels more like a companion, compare it with Mia as a different type of cat-themed product.
Comparison With Mia, the Talking AI Cat Companion Robot
HP-C28BT and Mia can both appeal to people who like cat-themed products. However, this is not a comparison between two robots. The comparison point is how each product brings a cat motif into everyday life.
HP-C28BT is an earbud product with a cute cat-shaped case. Mia is a cat-shaped talking companion robot designed for voice interaction, expressions, dialects, reminders, and daily presence.
| Comparison Point | HP-C28BT | Mia |
|---|---|---|
| Cat-themed role | Earbuds with a sleeping-cat-style charging case | Cat-shaped robot with voice, expressions, and daily prompts |
| Product category | True wireless earbuds | Talking AI cat companion robot |
| Shape | Cat-shaped charging case plus earbuds | Compact cat-shaped companion device |
| Main features | Music, calls, low-latency mode, water resistance, cat-shaped case | Dialects, expressions, voice interaction, Google Calendar reminders, weather updates, 15 English characters |
| Main purpose | Enjoy audio with a cute cat-themed accessory | Add small moments of voice, comfort, and companionship at home |
| Interaction | Bluetooth connection, earbud controls, charging case | Voice recognition, head touch, blinking, expressions |
| Conversation | Calling microphone only; the product itself is not a companion | Designed for voice interaction and friendly prompts |
| Best location | Bag, desk, commute, everyday carry | Desk, bedside, living room, family space |
| Long-term experience | A practical cat-designed accessory for daily use | Attachment through voice, expressions, dialects, and routine |
| Price | 8,980 yen including tax on the official page | From 9,800 yen including tax |
HP-C28BT suits people who want to carry a cute cat-themed item. Mia suits people who want a cat-shaped companion that talks and supports small daily routines.
In short, this is a choice between enjoying the cat motif as a practical audio accessory or as a small talking companion at home.
👇 Mia, the talking AI cat companion robot with dialects and a big personality

Conclusion
HP-C28BT is a memorable pair of true wireless earbuds built around a charming cat-shaped case.
It is easy to recommend to people who like cat accessories, want cute earbuds, or are choosing a small gift. The official page lists it at 8,980 yen including tax, making it a relatively accessible cat-themed gadget.
At the same time, HP-C28BT is not a pet robot or conversation robot. The comparison with Mia is based on the shared cat motif, not on identical product categories.
Choose HP-C28BT if you want a practical cat-designed audio accessory. Choose Mia if you want daily voice prompts, companionship, dialects, and a cat-shaped presence at home.
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