Retention holsters offer the user levels of protection against someone immediately grabbing their weapon from the holster. These style holsters are excellent for POLICE, Security personnel and anyone working in a high risk area. In essence they "retain" the weapon by requiring one, two or Level III movements or releases to acquire the weapon.
These Retention holsters also provide some protection that prevents the pistol from bouncing out of the holster while running or jumping. With proper training the handgun can still be extremely fast to deploy.