Review on Petsafe Flex Contacts for Collars: Enhanced 4-piece Replacement Set by Brian Hood

That's a great idea, but you can't tighten it with the little tool that comes with it. So it's best to tighten by hand. They also don't come with a blue tread lock to keep them from coming loose. Our dog wore this collar for a week and was able to scratch it enough to completely come off. Then she chewed up the black box to the point where it no longer works. Had to buy a replacement collar and it cost me $90 instead of what should have been more comfortable for the dog.