These are just like our adjustable in 1 inch only we make them in a strong 1 1/2 webbing   for stronger dogs, 

Medium

Size  (body) 21 to 30.

(Neck) 18 to 27 inches

Large

Size  (body) 24.5 to 36.5

(Neck) 21 to 33 inches

Ex Large

Size  (body) 27 to 43

(Neck) 25 to 37 inches

XX Large 

Body 32 to 54 Neck 30 to 50