This is an excellent general purpose collar and is very affordable.
To determine size, please add at least 2 inches for the 1/2" collar, 3 inches for the 3/4" wide collar and 4 inches for the 1" wide collar to your dog's neck measurements.
Sizes 12-14" are 1/2" wide.
Sizes 16-18" are 3/4" wide.
sizes 20-26" are 1" wide.