This OEM magazine is perfect for anyone who owns a Glock 31.Straight from the original manufacturer this Gen 4 magazine holds 15 rounds of 357 Sig ammo and is made of lightweight polymer.With a steel insert for added durability the quality of this product speaks for itself.Glock OEM Gen 4 Glock 31 Magazine (Polymer).357 Sig Caliber15 Round CapacityMade of Polymer with a Steel InsertIf you're looking to spend more time shooting and less time reloading then this mag is perfect for you.Order your Glock Magazine online today!Need some ear protection for the range? Find great deals on all in-stock Hearing protection available now from the brands you know and trust!Need some eye protection for the range? Find great deals on all in-stock Eye protection available now from the brands you know and trust!