PostGUARD. This safety device by HomeGUARD is specifically designed to improve home safety against burglary, preventing thieves from using the letterbox to access keys or unlock the door. The large capacity flexible see-through mesh fabric bag will accept bulky items without having to bend them to fit. The letterbox features letterbox locking pins and the bag has a lockable double zip pull. It can also help in protecting post from unwanted attention from inside the house, such as that of pets and small children. Please note that the bag is not indestructible and Aldridge will not be held responsible for damage.. Large capacity. Easy to install. Lockable letter plate. Strong see-through mesh fabric