Abstract: A cap is provided for disposition over the load bed of a pickup truck and includes opposite side wall structures having lower marginal portions for close juxtaposed position relative to upper marginal portions of the side walls of the load bed. Each side wall structure and the corresponding side wall include longitudinally spaced vertically separable mounting portions supporting the side wall structure from the side wall for angular displacement relative thereto about an axis extending along the lower marginal portion of that side wall structure. In addition, each pair of mounting portions includes support and guide means interconnecting therebetween operative to guide the corresponding side wall structure relative to the corresponding side wall for up and down movement relative thereto between a lowered position juxtaposed position the side wall and an upper limit position, the support and guide structure including spring means yieldingly biasing the side wall structure toward its upper limit position.