Each GLOCK magazine is constructed from a hardened steel insert encased in high tech polymer to protect the magazine and prevent deformation, even when dropped from a great height. The high quality spring and follower ensure reliable feeding from the first to the last shot. 13 - Round Capacity Constructed of Hardened Metal Encased in Durable Polymer Viewing Windows Polymer Base Plate Bulk packed By adding this item to your cart you understand and agree and certify that you will comply with all applicable federal, state and local laws and regulations. MAGAZINE CAPACITY NOTICE This magazine exceeds 10 rounds of capacity and may be restricted or prohibited in CA, CO, CT, DC, HI, IL, MA, MD, NJ, NM, NY, RI, VA, VT, WA, and select municipalities. It is the buyer's responsibility to verify local, state, and federal laws before purchase. Orders that cannot ship to a restricted address will be canceled and refunded.