There is a product on Keystone Country Store that is an STS for an Excaliber crossbow. It mounts in front of the stirrup and beside the deck. It touches the string at rest so that when it is fired it takes away the string oscillation and keeps it from going past the brace height. Has anyone used one of these? Is it worth the money? I was planning on buying it for my father for his Exocet. I've been setting it up for him so he can get his first bow kill this year!!! I want this thing super qiuet and driving tacks. What do you guys think?