This quick action clamp has a specially designed spigot to fit into the slot on the underside of a power tool guide rail. The spigot is compatible with the Festool FS, DeWALT and Makita guide rail system plus many others. To be sure, please check the clamp slot in your guide rail prior to ordering. The spigot is 11mm wide by 4mm thick and 60mm long. Owners of multi function workbenches can use the clamp as a hold-down simply by inserting the spigot into a dog hole. The single-handed operation leaves one hand free to steady the workpiece. The moving jaw has a resilient protective pad to prevent damage to delicate surfaces.-bg