Designed to fit the Stribog SP9 models with M-Lok receivers. The SRX was developed with the same mindset as the MREX rail lineup. Made from strong 6061-T6 aluminum, this durable receiver extension was built for comfort and ergonomics. The added 6 inches gives you an enhanced grip further down the Stribog while providing plenty of real estate for added accessories. The SRX was also designed around the option of adding a variety of suppressors, with plenty of ventilation to ensure a comfortable, cool grip even after extended suppressor use. SPECS: Length: 6.5 in Rail weight: 4.2 oz Overall weight: 6.2 oz Finish: Anodized black type 3 hard coat or FDE cerakote Mfg: Kinetic Development Group Llc