The RS Regulate AK-314MS is a rear-biased lower component of the innovative AK-300 Modular Side Mount System specifically engineered for Yugo/Serbian type rifles.RS Regulate AK-314MS Yugo Rear Biased LowerCompatible with OPAP NPAP and M21 pattern riflesPart of the modular AK-300 Side Mount SystemCompact dimensions: 5.71 x 0.55 x 1.88 inchesLightweight at 3.37 oz with matte finishRear-biased configuration for optimal mounting positionPerfect for Yugo and Serbian rifle owners seeking a reliable modular optics mounting solution that maintains the rifle's balance and functionality while providing a solid platform for scopes and sights.