I bought a H style harness and attempted to put it on Simba my Siamese, since he's so curious. I eventually was able to get it on but I wasnt' sure if I had it on properly. Whatever the case, I took him out on my frontporch and the minute he heard the machines working on the houses (I'm in a new development where there is house building), he jumped up towards me like, "Mom! Hold me!" Then he wanted back in the house. I think the next time I'll try the harness is if I go to PetSmart to have him explore there-all the cat toys and to make sure I"m putting the harness on correctly. I know Faline won't tolerate a collar, I tried one for her when she was a kitten, and she got it off. She gets her excercise chasing a toy stick and climbing the 6 foot cat furniture.