With the push of a button, ROBOSTOCK instantly transforms from a compact rectangle into an extended stock for all Glock models with the grip BACKSTRAP CAVITY → SIZE: 15 X 8 X 2 cm WEIGHT: 230 gm → Forward extension fits snuggly into the CAVITY → Rear extension attaches to forearm with hook and loop strap → ROBOSTOCK top rises into a cheekpiece → Compact size fits on waist belt & inside pocket → Shooting with open robostock provides more accurate & steady shooting due to increased stability. → Especially recommended for long range shooting. → Shooting with closed robostock attached to the arm provides accurate & steady shooting by eliminating wrist movement.