i have a similer one and i dont have a hook and it hasent done anything to my string of my darton

I have both and the closed loop one is a pain to get on the string loop. I bought one of the open loop type and have had no problems so far. I love the Winn releases I just wish they would put a better trigger mechanism and offer a buckle style glove in addition to the velcro one. I hate velcro on a hunting release.