@Meanlucario You use them for cats on walks. When teaching them on getting used to it, you basically put it on for an hour or so. The cat would initially think it's weird and most likely just lie down on its side due to the weight. They'll get used to it in a month or two.
@Scrabbleman We want to get one for our cat Silas since we refuse to let him out after he keeps on getting himself injured, and we want to use a harness to walk him since he takes his frustration out on the other cats, but not sure where to start.
@Meanlucario Get a harness slightly bigger than them. Like I said, they will initially act dead wearing them, just lying on the ground and doing nothing. They'll get used to the weight after several tries though.