Sliders are hospital grade HDPE (high density polyethylene) cassette covers. The slickness of this thick-ply material allows easy placement and removal of the grid and cassette even under the largest patients reducing technologist back strain. Helps protect the cassette from fluids, and protects patients from cassette bacterial contamination. The holder (sold separately) installs on the side of a portable x-ray machine without tools and allows convenient access to covers.