Size XS: neck 25-32cm, width 1.5cm
Size S: neck 32-40cm, width 2.0cm
Size M: neck 39-49cm, width 2.5cm
Size L: neck 48-58cm, width 3.0cm
Measure the widest part of the neck, around the middle where the collar sits, and choose the size your measurement sits inside, ideally near the middle. Measurements are taken by hand, and a difference of 1 to 2cm is normal. The ranges overlap; if your dog fits two sizes, the larger gives a wider, more padded band. Once buckled, two fingers should slide flat between the collar and the neck.