B5 Systems SOPMOD Government, Mil Spec, Black, Ships in Plastic Bag SOP-1351 Since 2011" B5 Systems has manufactured the Crane NSWC designed SOPMOD buttstock for the US Department of Defense. B5 is proud to offer the same stock to the general public. The SOPMOD features color matched steel hardware" no slip cushioned buttad" and dual water resistant storage compartments. The SOPMOD is made of milspec materials and finishes. Proudly made in the USA.