GSI International has introduced a unique, tamper-proof internal Gunlock that renders a stored semi-auto pistol totally inoperable by unauthorized persons. Unlike other gun locks, the new GSI Gunlock has no external features that can be compromised. Once the Gunlock is inserted into the pistol's magazine well and engaged, it is Impossible to remove without the key. The Body of the GSI Gunlock is precision machined to fit into the magazine well of the firearm. The key inserts into the base of the Gunlock. A turn of the key moves the Integral Locking Pin into firearm's chamber, securing the Gunlock in place. Using the GSI Gunlock requires No Modifications to the firearm and it is Impossible for ammunition to be present in the firearm while the Gunlock is in place. l Tamper-Proof l No Firearm Modifications l No Ammunition Present l No Electronics-No Batteries l Internal, Hardened Steel Components l Lifetime Warranty