This Kinetic Research Group Echo LOP Spacer Kit is a kit for those who want to upgrade their Echo with length-of-pull (LOP) spacers and a Four Lobe Thumbscrew for tool-less cheekpiece adjustment. The Echo Chassis has a LOP of approximately 12.9" with no spacers and just over 14" with three installed. Each spacer is 3/8" thick. All LOP hardware is included.FeaturesFits: Echo, Bravo and X-Ray Chassis (Ships standard on all current Bravo and X-Ray Chassis)Material: Reinforced polymer