JMac Customs AB-9R Arm Bar with Brace Adapter for 4.5mm Folding AKs 9in Rise Black. This version of the SM stock/brace adapter is specifically made for 4.5mm pin folding stocks. 4.5mm trunnions can be found in the SLR 104/106/107 UR/CR/FR. Cheek wield is adjustable by moving the stock/brace up or down on the adapter. Specifications for JMac Customs AB-9R Arm Bar w/ Brace Adapter for 4.5mm Folding AKs: Manufacturer: JMac Customs Color: Black Gun Type: Rifle Gun Make: Kalashnikov Gun Model: AK-47 Length: 9 in Weight: 3 oz Stock/Brace Material: 7075 T6 Aluminum Condition: New Features of JMac Customs AB-9R Arm Bar w/ Brace Adapter for 4.5mm Folding AKs Lightweight and Rigid Modular Design - Brace/Stock with many mounting options Integrated QD Sling Socket The AB-BA adapter allows you to install braces like the TailHook from Gear Head Works Anti-Rotational design Package Contents: JMac Customs AB-9R Arm Bar w/ Brace Adapter for 4.5mm Folding AKs Mounting bolt for lower hole What firearm models does the manufacturer say JMac Customs AB-9R Arm Bar w/ Brace Adapter for 4.5mm Folding AKs is compatible with? The manufacturer says that JMac Customs AB-9R Arm Bar w/ Brace Adapter for 4.5mm Folding AKs is compatible with AK-47JMac Customs AB-9R+AB-BA+SM-4.5: AB-9R Arm Bar with Brace Adapter for 4.5mm Folding AKs 9in Rise Black