ACR MS-2000M STROBE LIGHT - Military Green The MS-2000 (M) distress marker light has come a long way since you purchased ACR's original Firefly back in the 1960s. Here are a few of the new features found in all of our MS-2000(M) models: * Shield extends/retracts for omni- or uni-directional visibility * Waterproof down to 50ft (15.3m); * IR filter blocks all visiblelight (lets through only IR light) * Raised polarity indicators allow correct battery replacement in low or no visibility conditions * New braided steel retainer keeps battery door from being lost * Operates on 2 standard alkaline AA batteries - disposal causes no environmental impact * For extreme cold environments or long term storage, use 2 common lithium batteries * Blue filter distinguishes strobe from ground fire when in place Specifications Product Number: 3990 MS-2000(M)T * Size: 4.5 x 2.2 x 1.1 in (11.4 x 5.6 x 3.3 cm) * Weight: 4.0 oz (115 g) without batteries * Light Output: 250,000 peak lumens per flash * Flash Rate: 50 ñ 10 per minute * Light Dispersion: White-omnidirectional, IR-omnidirectional, Blue-unidirectional * Operating Life: 8 hours minimum-strobe; 2 hours minimum-incandescent * Visibility: Military tested at a distance of 6 miles (9.6km) on a clear dark night * Waterproof: To a depth of 50ft (15.3m); 200ft (61m) diver version available * Batteries: 2 AA alkaline or lithium batteries (not included) * Case Color: Black with olive drab flashguard * Construction: Case, lens and flashguard-high impact polycarbonate; IR filter-butyrate * Activation: Spark proof magnetic reed switch * Limited Warranty: 1 year * Federal Stock Number (FSN): 3990 only: 6230-01-411-8535