After holstering a weapon, there are different ways to keep it secure. This is important to prevent misfiring and loss of weapon control due to rapid movement or struggle with another person. Auto retention is one method of preventing unexpected weapon use.
Design
Once a weapon is holstered an automatic safety lock feature engages. It must be released in order to use the weapon. There are different types of auto retention. They are either released by the thumb, index or middle finger. Some models require drawing the weapon at an angle, while others have a straight-up draw, depending on the manufacturer.
Each weapon has a different type of design and shape, and requires a custom-designed fit. Beretta holsters, for example, will not fit the Glock or Ruger. This ensures a proper holster fit and performance.
Effort
One advantage to auto retention is that the user does not have to physically engage the device. Thumb straps take a conscious effort, while the auto retention feature takes place simply by holstering the gun properly. This is faster and less distracting. Pulling it back out does not require undoing a strap, but merely removing the gun at a specific angle. Some models require special release movements, while others do not. The fewer specifications there are, the faster the draw, which can sometimes mean the difference between life and death.
Purpose
Holsters with auto retention are usually associated with uniformed police or security officers. They are made for different types of uses, such as tactical, duty or concealment. Sports models do not put much emphasis on retention, since the idea is to draw and fire quickly, without concern over someone else taking possession of the firearm.