A lighter, smaller version of the Model 552, the Model 551 offers the same durability and function, but in a more compact unit. At 4 inches in length, this sight takes up less valuable rail space, leaving more room for a rear iron sight or NV mount.
" N Battery " 65 MOA circle with 1 MOA aiming dot reticle pattern " Compatible with Gen I-IV Night Vision Systems (tandem operation) " Includes rugged aluminum hood assembly and knobbed tool-less mounting bolt " Interfaces to standard 1" Weaver dovetail / Picatinny rail Waterproof to 33 feet 200 hours battery life 4" (102mm) Overall Length
<----65 MOA circle with 1 MOA aiming dot reticle pattern