Duty Retention Holsters - a holster designed with retention will help prevent a gun from being removed from the holster by anyone other than the person wearing it. Modern duty holsters have multiple hidden retention devices to this end. Frequently, retentive holsters are custom designed for a specific model of gun and combine optimum performance with safety. 
Below you will find holsters with various Retention mechanisms, such as the Thumb Break release, Thumb lever release, and trigger finger release.