Troy Modular Black Combat Grips are machined from aircraft aluminum billet. Grip converts easily into two sizes. 4 5/8 inch when completely assembled. 3 1/4 inch when in short (stubby mode). Thumb screw and low profile attachment screw included. Three part modular design. High capacity internal storage container for batteries or other items and is percision machined from aluminum and features knurled bands for a sure grip.