These covers are ideal for protecting a wide range of devices, components and sensitive units from vandalism and accidental damage as well as weather, dirt, dust and grime. Covers are designed to keep the enclosure at a temperature above freezing which allows the protected unit to be installed outdoors, in freezers, unheated warehouses or storage units. The radiant heat plate prevents LCD displays from becoming sluggish or freezing and operates on 12, 16.5 or 24 VAC/ VDC. The STI-7510-HTR/ STI-7511-HTR enclosures include an external thumb or key lock and have a choice of two enclosed backboxes.