This is a door reinforcement lock that protects against unwanted and unauthorized entry. It prevents lock bumping or lock picking in the locked position. ... There is no way to open this lock from the outside of the door and installs in minutes. Fits any swinging door, is tamper resistant, and is a child safe design.

Latch Guards Basics

The gap between the door and the frame is one of the weakest points, especially if the gap is wide enough to make the bolt visible from the exterior.

Latch guards are metal plates that cover exposed latches and keep them from being tampered with. In order to gain forced access, a latch may be cut or pryed; but a latch guard can keep this from happening.

Latch Guard Plates are typically made out of heavy gauge steel or stainless steel, so you can be sure they aren't easy to bend or cut.

Latch Guards are also known as Latch Sheilds or Latch Protectors.

Storefront Latch Protectors:

Storefront doors almost always have a large gap between the door and the jamb, leaving the latch or bolt exposed. This is especially true if a door has a mortise deadlatch. For this type of application, a storefront door security latch guard has a cutout to accommodate the cylinder for a Mortise Deadlatch, Mortise Deadbolt, or Mortise Hookbolt.

Offset Latch Guards account for when the jamb side of the door frame has a larger projection than the storefront door.

One of the best ways to make sure that your commercial building is secure, is to install a security plate that covers the gap between the full height of the space between the door and jamb. A full door latch protector effectively prevents prying and manipulation of the door. It is great for side and rear exit doors that are often hidden from main street traffic and the target of many break-ins. Another way to protect these vulnerable entrances is to install a security door bar that prevents the door from being removed, even if the door latch is compromised, the hinge pins removed, or the lock cylinder drilled.

Image result for Storefront Latch Protectors:

The Storefront Latch Guard protects storefront doors by covering the gap between the door and lock, preventing forced entry.