In 2012, RS Regulate began rolling out the first models of the AK-300 Modular Side Mount System, which now features six fully modular uppers and nine different lowers: a front-biased, a rear-biased, and a full-length lower for most Eastern European AK side rails; a front-biased and full-length lower for Yugo/Serbian rifles; a PSL and Romanian M10/RH10 rifles; a Century Arms proprietary side rail; and even a rear-biased lower for Czech vz. 58s.

• Trijicon RMR and Holosun HS507C Mount
• Common Usage: Trijicon RMR, RMR Type 2, Holosun HS507C
• Product Dimensions: 1.9 x 1.9 x 0.96 inches
• Weight: 1 oz