they say on the site you need a teather cord but you can get away with out it. i ran my 600 prob. 40 times in jeans and a leather coat. LVD pushes boots,leather gloves and a coat. if you go under 10.5 they will tell you to get pants as well. I put my 1k into the 9s and they werent to happy with that lol. you can get away running with out the teather.