The invention is a kit for attaching to a truck cap to enable the cap to be lifted off of and lowered onto a truck by lines from above. The kit includes: a first rail and a second rail, each configured to attach to the truck cap; a first pair of sliding masts for releasably attaching to the first rail and a second pair of sliding masts for releasably attaching to the second rail. Each of the sliding mast includes: a sled which is captured by the rail, and is slidable along the rail, and is adapted to be secured at various points along the rail; and a brace with one end attached to the sled and the other end adapted to receive one of the lines. In another aspect, the kit includes multiple lifting devices.