A four-zone stereo with chartplotter control for well under the price of an Apollo. It suits a boat that will add amplifiers zone by zone.
Amazon $427.86The Clarion CMM-30 rates 3.6 among dash and panel marine stereos; the Kenwood KMR-M300BT rates 2.6 among gauge-hole ones. The Kenwood KMR-M300BT costs $128.86 less ($299 vs $427.86).
Prices were last checked November 9, 2026. Product prices and availability are accurate as of that date and are subject to change; the price and availability shown on Amazon or the retailer's site at the time of purchase apply. As an Amazon Associate we earn from qualifying purchases.

A full-featured gauge-hole stereo for a small boat or powersports dash. Spend more on the eXcelon KMR-XM500 only if you want its 5 V pre-outs and longer warranty.
Amazon $299Scores side by side
These two sit in different mount classes (dash and panel and gauge-hole), and each is scored against the reference points for its own class, so a rating says how well each does among its own mount peers. How we rank explains each factor.
| Factor weight | Clarion CMM-30 | Kenwood KMR-M300BT |
|---|---|---|
| Overall rating | 3.6/5 | 2.6/5 |
| Amplifier power 20% | 42 25 W RMS x 4 at 4 ohm | 19 19 W RMS x 4 at 4 ohm |
| Zones 15% | 100 4 zones | 0 single zone |
| Pre-amp outputs 10% | 43 4 RCA output sets | 29 3 RCA output sets at 2 V |
| Features 25% | 70 NMEA 2000, SiriusXM-ready, weather band, Bluetooth, USB playback | 50 SiriusXM-ready, weather band, Bluetooth, USB playback |
| Water rating 10% | 70 IP66 front | 70 IP66 front |
| Display 10% | 66 3 in color | 58 2.7 in color |
| Warranty 10% | 0 1-year warranty | 0 1-year warranty |
Specifications
| Clarion CMM-30 | Kenwood KMR-M300BT | |
|---|---|---|
| Audio | ||
| Amplifier power (RMS, 4 ohm) | 25 W x 4 RMS | 19 W x 4 RMS |
| Zones | 4 | 1 |
| RCA output sets | 4 | 3 at 2 V |
| Sources and control | ||
| Bluetooth | Yes | Yes |
| USB playback | Yes | Yes |
| Phone app | No | No |
| SiriusXM-ready | Yes | Yes |
| NMEA 2000 | Yes | No |
| Wi-Fi or AirPlay 2 | No | No |
| Weather band | Yes | Yes |
| DAB+ | No | No |
| CD player | No | No |
| Camera input | No | Yes |
| Build | ||
| Mount | Panel cutout | Gauge hole |
| Front water rating | IP66 | IP66 |
| Display | 3 in color | 2.7 in color |
| Warranty | 1 year | 1 year |