Ocean Kayak Scupper Stoppers - Pack of 2, (Large, Red) The stoppers' soft material is comfortable against the body even when installed under the seat. A multi-ribbed design offers a better seal, helping the paddler stay dry while paddling. Scupper Stoppers are completely round in shape and do not fit oval-shaped scupper holes. The stoppers are available in extra-small, small, medium, and large sizes. Includes a pack of two large red stoppers.