ORIGINAL: wingchaser_labs
STS makes one and I forget the other company I know of. You gain a couple feet per sec and take some string vibration out of your shot. I know a guy who got tenis elbow from shootin so much and he put the sts on and has never had a problem since. Some people like em and makes a difference on their bow and some don't. WCL
Obviously on his bow arm....huh, I've never heard of that before...there's that much vibration from some bows??