The C-O series are original single barbed straight and reducing connectors. These parts have no parting line on the barb. Tubing can be started on the barb before any expansion begins. Also, it will expand the tubing by 43% when completely inserted. Available materials are white nylon and natural polypropylene. In addition, straight barb sizes are 1/16 inch, 3/32 inch, 1/8 inch, 5/32 inch, 3/16 inch, and 1/4 inch. Reducing barb sizes come in combinations ranging from 1/16 inch to 3/8 inch.