USED JMac Customs 1913 Adapter for MP5 and Clones Hardcoat Anodized Black RSA-MP5. This adapter will fit the Standard/Full Size MP5 as well as HK33 (556). It has a picatiny rail machined on the rear which allows you to install 1913 style stocks/bracesCheek wield is adjustable using any stock/brace by simply attaching the stock/brace higher or lower on the picatiny rail Specifications for JMac Customs 1913 Adapter for MP5 and Clones: Manufacturer: JMac Customs Color: Black Gun Make: Kalashnikov Gun Type: Rifle Fabric/Material: 7075-T6 Aluminum Mount Type: AK Mount Features of JMac Customs 1913 Adapter for MP5 and Clones 1913 Adapter for MP5 and Clones Package Contents: JMac Customs 1913 Adapter for MP5 and Clones JMac Customs RSA-MP5: 1913 Adapter for MP5 and Clones Hardcoat Anodized Black