Ergo Grip .002 in Thick Barrel Nut Shims 4 Pack. ERGO shims can be used individually or combined together. Kit comes with (4) .002in shims. Specifications for Ergo Barrel Nut Shims - 4 Pack: Manufacturer: ERGO Gun Model: AR-15 Quantity: 4 Features of Ergo Barrel Nut Shims - 4 Pack .002" thickness; pack of 4 Package Contents: Ergo Grip Barrel Nut Shims - 4 Pack What firearm models does the manufacturer say Ergo Barrel Nut Shims - 4 Pack is compatible with? The manufacturer suggests that Ergo Barrel Nut Shims - 4 Pack is compatible with AR-15Ergo Grip 4964-4PK: .002 in Thick Barrel Nut Shims 4 Pack