SKU: MLOK(5.5")SET-BCA New Rail Design5.5" MLOK1 Rail Nut2 Washers8 Screws1 Hex KeyMADE IN THE USAMLOK Rails:Inner Diameter: 1.33"Outer Diameter: 1.57" Instructions: Tighten barrel nut to 60 to 80-foot pounds and the six rail mounting screws to 35-inch pounds. Blue lock tight could be used to secure rail screws.Manufactured at Bear Creek Arsenal in Sanford NC, MADE IN THE USA{{widget type="Magento\Cms\Block\Widget\Block" template="widget/static_block/default.phtml" block_id="42"}}It is the responsibility of the consumer to ensure all state, local, federal, and ITAR regulations are followed