We recently picked up two of these collars for our dual purpose K9's. One being a 90 lb German Shepherd and one being a 55 lb Mal. The shepherd is nearing the end of his career and we have been working for years on keeping him quiet during K9 announcements. Using gentle pressure on the DDC any time he barks has made a world of difference in just two sessions working with him. For the Mal, she is brand new and despite being small can alligator roll with the best of them on a lift off. Her handler is rather petite and the DDC has given her the ability to do lift offs with no rolling and little effort, all with almost zero conflict. We are excited to keep using this tool for our differing needs. It is very convenient to be able to throw in a pocket to always have with you in case the need arises for it. This will be standard equipment for all of the K9's in our program moving forward!
For reference we got the Shepherd a 17 inch, which is fairly snug. A 17 1/2" would probably be better but he is not wearing it on a regular basis anyway. The Mal has a 14 which is just right.