Check the listing for details. STAYPUT Bungee Shock Cord Clip "extras if need" 3 sizes Knobs, Pulls, & Screws. Color: BLACK, Condition: New. Listed at 10.06 USD. Ultimate Stayput Shock Cord Clips / Loops... Color: BLACKYou will receive in each Set, Depending on the Set you choose....1. choice : Bungee Cord Clips only...Bungee cords, Caps to hold the cord, Clips for the back of the cord Cap.Other options include if chosen :2. choice: Bungee Cord Clips adding Pull cords (for easier pulling of bungee), & 3. choice : Bungee Cord Clips adding Knobs that receive the bungee cord. & 4. choice: "Full set" Bungee Cord Clips adding Pull Cords & Knobs.Both the above plus also comes with Screws to attach the knobs.5. choice: Bungee Cord Clips adding Pull Cords & Knobs.· Simple installation in varying thicknesses of fabric without the need for any special tools.· The large back plate provides a greater contact area with the fabric reduces the risk of tearing out and damaging the fabric.· Brass machine pressed crimps on the shock cord will not rust or pull off.· The fitting can be removed & re-fitted with a new cord without damage to the fabric, making the Stayput Loop the best and most versatile on the market.· Knob diameter: 1 1/8" - Knob height 9/16"· Shock cord diameter: 3/16"· When relaxed - shock cord loop end to center of knob isSmall:.......OUT OF STOCK !!...... 2 1/2" Overall length is 2 1/2" end to end.When pulled tight - shock cord loop end to center of knob is 2 1/4" to 4" end to end (max. extension when pulled tight)Standard:....... 3 1/2" Overall length is 3 1/2" end to end.When pulled tight - shock cord loop end to center of knob is 3 1/4" to 5" end to end (max. extension when pulled tight)Large:............. 4" Overall length is 4 1/2" end to end.When pulled tight - shock cord loop end to center of knob is 4 1/4" to 6" end to end (max. extension when pulled tight)To attach to your cover you will need to put a small hole in the canvas, less than 1/4 inch.They are manufactured from UV stabilized nylon and acetyl compounds. Originally designed extensively for the marine market, are now used in all areas of fabric fastening. If you need something different than listed, let me know happy to accommodate. Thanks