For larger breeds with longer limbs, or breeds in between sizes, always size up. Always monitor a pet post-surgery to ensure collar is working properly. Some pets may be able to maneuver around any collar. Designed for pet use only. Not intended to be used as a flotation device.
My only complaint is it's not very durable. She'd catch it on tree branches or bushes in the yard, and it tore the lining in several areas. I had to throw it away after the stitches were removed.