The Re-Traxt 4-SC for Descent PFD is shock loaded tubular webbing that absorbs impact from towing and stows compressed, close to your side. SC, stands for Self Centering and has a velcro tab that mates up with the velcro on the back of the Descent PFD. The Re-Traxt is adjustable so the user can select mating placement so that the web rides in close at your side. Comes with a special wide gated paddle biner and black oxide stainless steel ring as shown.