The SIG SAUER M400 SDI XSERIES packs a rich set of features and upgrades into the M400 platform delivering an advanced performance rifle right out of the box. The M400 XSERIES lower features fully ambidextrous controls, including bolt catch & release, selector switch, charging handle and mag release. Also unique to the XSERIES is a precision machined lightning cut upper and lower with a handguard clamp system designed to minimize deflection when using mounted accessories. Other features include a hybrid flash hider/compensator, 2-Stage Matchlite Trigger and Magpul SL Telescoping Stock. The TREAD branded accessories that can be purchased seperately are: M-LOK handguard wit Mfg: Sig Sauer, Inc.