JMac Customs SS-8R Skeleton Stock for 4.5mm Folding AKs 8in Black. 5mm pin folding stocks. 4.5mm trunnions can be found in the SLR 104/106/107 UR/CR/FR. This stock adapter like the rest of the SM line will allow you to install all of our Arm Bar and Stocks as well as SIG style stocks. Cheek wield is adjustable by moving the stock/brace up or down on the adapter. Specifications for JMac Customs SS-8R Skeleton Stock for 4.5mm Folding AKs: Manufacturer: JMac Customs Gun Make: Kalashnikov Gun Model: AKM Stock/Brace Material: 7075 T6 Aluminum Color: Black Finish: Hard Coat Anodized Weight: 6.48 oz 6.5 oz Length: 8 in Features of JMac Customs SS-8R Skeleton Stock for 4.5mm Folding AKs 8'' Stock Package Contents: JMac Customs SS-8R Skeleton Stock for 4.5mm Folding AKs What firearm models does the manufacturer say JMac Customs SS-8R Skeleton Stock for 4.5mm Folding AKs is compatible with? The manufacturer suggests that JMac Customs SS-8R Skeleton Stock for 4.5mm Folding AKs is compatible with AKMJMac Customs SS-8RP+SM-4.5: SS-8R Skeleton Stock for 4.5mm Folding AKs 8in Black