I used one that my sister got me for Christmas a few years ago. I pulled it out of the packaging. It has a flashlight and a radio. But I did not want it for them. I wanted to put a sunscreen over the puppy pen, and thought I could clip it to the eyelet and then pitch the handle thing over the kennel fencing and and go out there and draw it over. It worked.
I have used some for holding doors or gates open. But mostly, I don't use them at all. If they snap, you can lose an eye. It is true that the dog constantly applies pressure, and I just don't trust that thumb switch to hold the dog back if it really wants to go for something. I use regular leashes, and that is enough area for most of what we do. When we are ready to go off-lead -- the only time I would consider a flexi -- well, then we go off-lead.
Jenna, RN CGC & Babs, CD RA CGC HIC
Heidi, RA CGC
SG3 Odessa, SchH1, Kkl1, AD
Ninja, RN CGC & Milla, RN CGC
Joy, Star Puppy, RN CGC
Dolly CGC & Bear CGC