The M400 TREAD is an optics ready, aluminum frame rifle. TREAD features a 16" stainless steel barrel with a free-floating M-LOK handguard, a single-stage polished/hard-coat trigger, ambidextrous controls, a Magpul(TM) SL-K 6 position telescoping stock, a mid-length gas system, and is available in 5.56 NATO. Other TREAD branded accessories (purchased separately) include: M-LOK handguard with lightening cuts to reduce weight, available in 13" and 15" lengths; 3 chamber compensator; Ambidextrous charging handle made of aircraft grade aluminum and a dual roll pin design; ROMEO5 optic featuring a 2MOA dot with ten illumination settings, MOTAC Mfg: Sig Sauer, Inc.