Don't do what I did. I bought a reg. collar from petco. I left it on Sandy for about 15mins while she was playing outside. She was fully brushed before I put the collar on.
When I reached down and pet her it in kitchen I found a medium sized mat under her ear. I tried and tried to get it to detangle and it just wasn't happening. It was tight. So off it had to go. Luckly it was in a spot that's hard to notice and will blend in with in her neckline that's already shaved. It might make a difference that I think we are going thru coat change.
I think I will just stick to using my all in one parcute lead for now until I get a better collar.