These KCI USA's Glock pattern magazines are constructed with a hardened steel insert that are encased in polymer. The polymer molding helps to protect the magazine body from damage and deformation from regular use. For use in Glock patterned pistols. Fit and function in PCC's is not guaranteed.DISCLAIMER: This product is not manufactured, authorized, endorsed, or warranted by GLOCK. GLOCK does not warrant or represent that this product is compatible with GLOCK pistols.