Cat-A-Pillar is a non-conductive, low density polyethylene spacer strip consisting of 8 foldable segments. Each segment allows for 1/8" spacing. It's easy to calculate. Determine the depth of the box to the surface and tear or cut the number of 1/8" segments needed. Snap over screw (no need to remove) and rotate a Cat-A-Pillar so that the slot faces away from the device. Installs quickly on single or multi-gang boxes. Reusable and can be used as a shim or a plastic washer to straighten crooked devices.