Boss Audio MGR300B Marine In-Dash Gauge Stereo — 3.15" Round Mount, Bluetooth (153-MGR300B)
Free returns on all eligible orders
You have 30 days to request a return. All sale items are final sale.
Marine Stereo That Fits Where a DIN Slot Won’t
The Boss Audio MGR300B (153-MGR300B) is a marine-rated in-dash stereo designed to mount in a standard 3.15” (80mm) round gauge hole — the same cutout used for speedometers and depth gauges. If your helm panel doesn’t have a traditional single-DIN slot, the MGR300B is the solution: full AM/FM and Bluetooth audio in a compact, weather-resistant gauge-format housing.
Key Features
- Gauge-Mount Form Factor — 3.15” (80mm) round cutout; fits standard helm gauge holes; no DIN slot required
- IPX5 Water-Resistant — rated for spray and splash; conformal-coated PCB for additional moisture protection
- Bluetooth Audio Streaming — stream music from Spotify, Pandora, and other apps wirelessly from your smartphone
- 60W × 4 Channel Output — 240W total max power; drives up to 4 speakers
- AM/FM Tuner — switchable US & EU tuner frequencies; preset memory retained if battery is disconnected
- USB Port & USB Charging (1A) — plays MP3/WMA files; charges connected devices
- Aux-In — compatible with iPod®, iPhone®, smartphones, and MP3 players
- Front Pre-Amp Outputs — connect an external amplifier for expanded system capability
- Firmware Updates via USB — keep the unit current without dealer service
Parts Desk Insights
SKU 153-MGR300B is the Boss Audio MGR300B gauge-format marine stereo under the Boss Audio Systems brand. The round gauge-mount form factor is the primary selling point — position this for customers with helm panels that lack a DIN slot, particularly on older vessels or compact center-console layouts where gauge clusters dominate the dash. Confirm the customer has an 80mm (3.15”) gauge hole available or is willing to cut one. At 862g it’s a lightweight install. The switchable US/EU tuner makes it a viable option for customers who cruise internationally. Pre-amp outputs allow future amplifier addition if the customer wants to expand the system later.
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 3–4 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.