RS Regulate Yugo Rear Biased Lower Modular Side Mount Fits Yugo/Serbian Type Rifles Matte Finish Black Not Compatible with Folding Stocks. 58s. Specifications for RS Regulate Yugo Rear Biased Lower Modular Side Mount Fits Yugo/Serbian Type Rifles Matte Finish Black Not Compatible with Folding Stocks: Manufacturer: RS Regulate Color: Black Finish: Matte Black Additional Features: Yugo/Serbian Type Rifles Side Mount Handle Color: Black Blade Finish: Matte Case Finish: Matte Features of RS Regulate Yugo Rear Biased Lower Modular Side Mount Fits Yugo/Serbian Type Rifles Matte Finish Black Not Compatible with Folding Stocks: Yugo Rear Biased Lower Package Contents: RS Regulate Yugo Rear Biased Lower Modular Side Mount Fits Yugo/Serbian Type Rifles Matte Finish Black Not Compatible with Folding Stocks