
I used them because I was in another country, and the sire's owner/breeder doesn't use progesterone testing so couldn't recommend a good vet/company to do it. I figured using them in addition to letting the dogs be together was at least something.
The corners are sharp (someone else said they snip the corners first - should have thought of that) but aside from that very easy to do, and I got the colour change about the same time as other signs suggested she was ovulating. Got 7 puppies from two matings starting 2 days after the colour change.
Got mine from here
http://www.ovulationpads.info/I don't know that I would use them if I were breeding to a stud from here - I'd likely do progesterone testing if anything, but being so far away from home I wanted a double check. Having said that they were correct.