Armaspec AR15 Gen4 C/H/H2 Stealth Recoil Spring Kit SS/Black. To eliminate any potential failure points we changed the screw to a roll pin across the plastic end piece and the cap is machined on the rodm replaced the snap ring with a washer. Compatible with AR-15 with carbine-length buffer tube. AR10 version is available please find under AR10 parts. Most bolt carriers have a rear opening of over .60 there are a couple of bolt carriers in the market place that have a rear opening of under .60 and will not function with the SRS. Specifications for Armaspec AR15 Gen4 C/H/H2 Stealth Recoil Spring Kit: Manufacturer: Armaspec Color: Stainless/Black Gun Make: AR Platform Gun Model: AR-15 Length: 7.8 in Condition: New Country of Origin: USA Features of Armaspec AR15 Gen4 C/H/H2 Stealth Recoil Spring Kit Coming Soon Package Contents: Armaspec AR15 Gen4 C/H/H2 Stealth Recoil Spring Kit What firearm models does the manufacturer say Armaspec AR15 Gen4 C/H/H2 Stealth Recoil Spring Kit is compatible with? The manufacturer says that Armaspec AR15 Gen4 C/H/H2 Stealth Recoil Spring Kit is compatible with AR-15Armaspec ARM253-AR15KIT: AR15 Gen4 C/H/H2 Stealth Recoil Spring Kit SS/Black