When someone goes overboard, the seconds between the alert and the recovery display decide whether it ends as a drill or an emergency. Marine safety survival starts with picking a signalling device that matches your boat, crew, and the water you operate in. The four listings here fall into two clear groups: transmitters that send a position after a fall, and a visual warning kit that helps rescuers see you.
All four listings are marked New, and the listed prices run from USD 29.99 to USD 364.55. The ONWA KS-33R and both sMRT Alert beacons are man-overboard safety equipment, while the JDMTECH four-piece magnetic LED strobe is a multi-use visual marker that can work as a boat flare kit and for marine activities.
Quick take
If your priority is a transmitting beacon that can share someone's position, the ONWA KS-33R and the two sMRT Alert listings are the ones to compare. The ONWA is a GPS tracker with a buzzer and LED flashing indicator. The sMRT Alert adds digital selective calling, so nearby vessels can be alerted directly while the beacon continues updating the person's live location. If you want the lowest-listed-price visual option in this set, the JDMTECH strobe kit is the one to look at.
Listed price comparison
| Product | Listed Price | Price Bar |
|---|---|---|
| ONWA KS-33R AIS MOB Positioning Beacon Tracker Marine Emergency GPS Tracking | USD 177.65 | |
| sMRT Alert AIS DSC MOB Marine Safety Man Overboard Beacon SOS Emergency | USD 364.55 | |
| sMRT Alert MOB | Marine Safety | Man Overboard Beacon | SOS | Emergency | USD 333.33 | |
| 4pc Magnetic Emergency Hazard Warning Safety Road Light LED Strobe Beacon Lights | USD 29.99 |
Decision matrix
| Product | Best for | Keep in mind |
|---|---|---|
| ONWA KS-33R | A life-jacket-mountable AIS beacon that shares GPS tracking with plotters | VHF DSC is covered by the sMRT Alert entries |
| sMRT Alert AIS DSC MOB | Crews who want VHF DSC plus AIS updates from one unit | Highest listed price in this set |
| sMRT Alert MOB | Same MOA-50070 part with a lower listed price | Description focuses on compact marine use rather than the AIS/DSC specifics |
| JDMTECH 4pc magnetic strobe | Multi-use visual warning for marine and roadside duty | Transmitting beacons in this set carry the AIS, DSC, or GPS positioning features |
Product notes
ONWA KS-33R AIS MOB Positioning Beacon Tracker Marine Emergency GPS Tracking
The ONWA KS-33R centers on AIS GPS target tracking. The description says the beacon transmits GPS target tracking over AIS, works with plotters and onboard navigation systems, mounts on a life jacket, and runs for at least 24 hours of continuous operation. It adds an LED flashing indicator and buzzer, which helps when the person is close but hidden by water or darkness. VHF DSC appears only in the sMRT Alert descriptions, so if a distress-call channel matters, the Wescom beacons are where to find it. On the listed price bar, the KS-33R sits between the strobe kit and the sMRT beacons.
sMRT Alert AIS DSC MOB Marine Safety Man Overboard Beacon SOS Emergency
The Wescom sMRT Alert at the top of the price range combines VHF DSC and AIS in one man-overboard beacon. The description says DSC automatically alerts nearby vessels, AIS continuously updates the overboard person's live location, and dual GPS and Galileo receivers help make detection faster. It also mentions water-activated alerting, two-way signalling, and app-based status checks. The trade-off is price: this entry has the highest listed price in the group. If you want the full AIS/DSC feature set and the MOA-50070 part number, this is the more detailed of the two sMRT Alert entries.
sMRT Alert MOB | Marine Safety | Man Overboard Beacon | SOS | Emergency
This second Wescom entry uses the same MOA-50070 part number but arrives at a lower listed price. Its description frames the device as a compact, lightweight alert for boats, yachts, RIBs, and sailing vessels, which makes it easy to match to different deck layouts. The description focuses on all-round marine ease rather than the longer AIS/DSC and dual-GNSS breakdown in the other sMRT Alert entry. For buyers who only need the sMRT Alert itself and prefer the lower listed price, this entry delivers the same part number.
4pc Magnetic Emergency Hazard Warning Safety Road Light LED Strobe Beacon Lights
The JDMTECH four-piece magnetic strobe is the visual-marking end of this marine safety survival set. Its description says the lights use a 360-degree beam angle, attach magnetically, offer nine flashing modes, include a white LED flashlight mode, and are waterproof. The same text points to boat-flare kit and marine activities, so it can double as a road flare or deck marker. For position transmission, the three beacons in this set are the ones with AIS, DSC, or GPS features; the strobe's listed functions are visual. It is best treated as a high-visibility supplement to a transmitting beacon, not as a replacement for one.
Final recommendation by use case
For a dedicated man-overboard transmitter, the sMRT Alert AIS DSC MOB at USD 364.55 gives you the transmitted-alert package that includes VHF DSC, AIS updates, and dual GNSS receivers in one unit. If that feature set is what you need, it is the listing to choose.
If you want the same MOA-50070 part but do not need the longer description, the second sMRT Alert entry at USD 333.33 is the same man-overboard beacon with a lower listed price.
If your navigation ecosystem is built around AIS and plotters, the ONWA KS-33R at USD 177.65 is the lower-priced AIS tracker in this group, with GPS tracking, a buzzer, and LED flashing, plus a stated 24-hour runtime.
If marine safety survival means carrying a visual warning light that is also useful for roadside emergencies, the JDMTECH 4pc magnetic strobe at USD 29.99 is the lowest-listed-price visual option, while the three beacons are the ones that carry position-transmission features.
