(Certified Scuba Instructor at Scuba.com)
Hello Mary, you use these to make your own sling. This is the wish bone you use at the end of the tube. Also here is the web link: http://www.scuba.com/scuba-gear-251/041171/Mares-Pneumatic-Speargun-Air-Pump.html
. If you have any other questions or would like to place an order please feel free to give us a call at 1.800.347.2822.