Compression caps hold the retraction cord deep in the sulcus, creating a wider opening. Ensures a dry, clean area and a well-defined gingival margin. Stops bleeding by compression. The flat base provides an optimal bite surface for the patient and Comprecaps are made of 100% cotton. Roeko Comprecap Preformed Compression Cap Cotton Size 5 Large 12.5 mm Refill 400/Box.