The Geissele Super Modular Rail MK2 (SMR) was designed to be a cost effective option to our SMR MK1. Our SMR MK2 is designed to fit the M4 Carbine and all mil-spec AR-15 variants. The SMR MK2 was designed to do a good job in meeting the ten design specifications for a good M4 weapon rail while being a cost effective alternative to the SMR MK1.

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