The PROLOCK PLK05 (93178) hard caps bring an added level of layered, armor-like protection to your Prolock foam or gel kneepads. These hard-wearing, shatter-resistant polyethylene caps protect your knees even on the roughest and most abrasive surfaces, from roofing shingles to concrete flooring and their smooth plate surface allows for easy side-to-side and pivoting movements. Attaching them to your existing Prolock kneepads is simple and tools are entirely optional, just twist the four thumbscrews into their corresponding anchors either by hand or with a hex key or Allen wrench for a secure fit. Remember, when a task calls for working on your knees, let PROLOCK knee pads take the strain so you don't have to.