I have only put the back ones on Uni, b/c that's where her problem is. Yes there is a difference between the backs and fronts. That's another reason why I liked these. You zip it down, stick the paw in, move the hair out of the way and zip up. There is elastic on the back around the ankle/achilles tendon is.
It will take a bit of training for them to get used to it. What i did was as soon as I put them on, I got out the toys and have her walk around with me and give treats. She soon forgot about them.
