Ergo Grip Spike Block f/AR-15 Black. The Ergo Spike Block is one of the most useful maintenance accessories available for an AR15. Simply bolt or clamp securely to a bench or other work surface place an AR onto the block inside the magazine well and the rifle is held in place for cleaning maintenance or storage. Get your Ergo Spike's Block today. Specifications for Ergo Grip Spike Blocks for AR-15: Manufacturer: ERGO Gun Model: AR-15 Gun Type: Rifle Color: Black Quantity: 1 Features of Ergo Grip Spikes Block: 6 1/8" H x 2" L x 4 5/16" W; 1/4" mounting holes Package Contents: Ergo Grip Spike Blocks for AR-15 What firearm models does the manufacturer say Ergo Grip Spike Blocks for AR-15 is compatible with? The manufacturer suggests that Ergo Grip Spike Blocks for AR-15 is compatible with AR-15Ergo Grip 4996: Spikes Block Black