Non snap-in studs only for series 2600 & 2700. Order separately. Retaining rings are required for stud length dash numbers 3-5 and greater. Studs with smaller dash numbers are self-captivating and retaining rings are not used. Solid rings are used to hold stud assemblies stationary to top panel. Split ring allows stud assemblies to move freely within the top panel. Steel, cadmium plated.