Tug Pull Down Ballstretcher BlackTUG is a silicone ballstretcher with pull down attached rubbery wings designed to add hanging weight but with more accuracy and comfort than most tug down ballstretchers. We include a carabiner clip that connects the two wings so the weights you add stay centred directly under the ballsack this puts the heavy tugging where it works best, straight down. When you add weight, the stretchy wings pull down and tighten the grip at the bottom of the B ring