The 3/4" quicksnap bungee strap replaces the strap that comes standard with your ecollar. It makes it much easier to get the collar on with the quicksnap, and the bungee allows for more flexibility and breathing room for your dog.
 
It comes in 2 sizes: standard which fits neck sizes from 11.5" to 24", and small which fits neck sizes from 8" to 14"