Caliber 9mm & .300 BLK Subsonic - Accessories Alpha & 3-Lug - Weight 3.17 oz - Length 3.69 - Diameter 1.37 - Materials Grade 5 Titanium & Grade 9 Titanium - Ships With Spectre 9 Tool Spanner Tool Spectre 9 Piston Housing - dB Readings - CALIBER DB AVERAGE - 9MM Pistol 138.6 dB - 9MM Subgun 139.4 dB - 300 BLK Subsonic 145.0 dB -Features - Constructed completely out of titanium. - Designed for 9mm pistols and subguns. - Ultra-lightweight & compact for minimal impact - Full auto rated- one of the few that can run on a full-auto Glock.