With 70,000 peak candlepower, this high intensity Xenon strobe clearly marks a crew-overboard site with each brilliant flash. It automatically rights itself and activates when in the water and begins strobing, operating for up to 60 hours on a 6-volt lantern battery. Perfect for commercial marine, petro-marine, cruisers and any application needing a reliable COB light.
The SM-2 is the industry standard for buoy lights. Its durability is put to the test every day on ships and oil rigs around the world and is the choice of the United States Navy and Coast Guard. ACR has long solved the issue of condensation in buoy lights which is a common occurrence on some other brands.

The supplied mounting bracket holds the SM-2 secure in the roughest of conditions but it is still readily accessible when needed in an emergency. With its easily replaceable 6 volt lantern battery power source, the SM-2 will give years of service and be ready when called upon.
• Upgraded, polycarbonate blend case is extremely durable; withstands vigorous use [drop-tested 100 ft. (30 m)]
• UV, temperature, and chemical-resistant
• High intensity Xenon strobe gives 360° visibility for more than 3 miles (4.8 km)
SPECIFICATIONS
Product Number | 3940.1 |
Size | 3.8” x 4.8” (35 x 12 cm) |
Weight | .75 lbs (794 g) |
3.94 lbs (1.13 kg) with battery | |
Material | UV stable polycarbonate blend |
Color | International orange |
Operation | Throw unit overboard or turn upright and light will begin to work |
Waterproof | Drop tested 100 ft (33 m) into water |
Battery Type | 6V Lantern style battery |
Beam Angle | Omnidirectional 360° |
Visibility | 60° visibility for over 3 miles (4.8 km) |
Flash Rate | 60/minute |
Lamp | Xenon flash tube |
Certfication | Complies with IMO/SOLAS/LSA Code; USCG 161.010 & USCG 161.110 approved; Tested to UL 1196 |
Accessories | ▪Bulkhead bracket (P/N 9438.1 ) |
▪Top cap and pole strobe assembly (P/N 9021.1) | |
▪Repair kit (P/N 9286) | |
▪Stainless Steel Lifeline Bracket (P/N 9566) | |
Limited Warranty | 1 year |
A Matter of Balance
Marker lights, by design, need to float upright for maximum visibility. The 6 volt lantern batteries provide the ballast for these lights. Although batteries may be the same size, the
different chemistries cause them to have varying weights. It is imperative that only the 6 volt battery models suggested are used.
Too little ballast and the light will lie on its side and be ineffective; too much weight and the light may sink. If there are any doubts to the appropriate weight of the battery, test the light by placing it in shallow water. If it floats upright, it is good, however, if the SM-2 sinks, the battery is too heavy.
Suggested Battery Types
Screw Terminal Batteries: ANSI/NEDA: 915, 915C, 915D, 915AC Duracell: M915, PC915;
Rayovac: 942, 944 ; Eveready: 510S
Optional Stainless Steel Lifeline Bracket
P/N 9566
Attaches to SM-2 as a mounting bracket to sailboats fitted with a lifeline
Bracket does not comply with IMO/SOLAS/USCG due to bracket configuration
Read more : Line Throwing For Marine