These are HANDMADE right here in our shop.  I started using them on my Yorkie pups after the velcro style failed.    
 
We offer this as a set of 6 collars as a multi-color pack and in the sizes listed below.
 
Sizes:  
TOY/SM: 4" - 8" (approx)
MD/LG: 8" - 16"  (approx)
XL/XXL:  16" - 24" (approx)
 
These are adjustable slip knot style.   These will adjust down to the smallest circumference listed and when fullly expanded will be the larger circumference listed for the size selected.   NOTE:  These are all handmade so the circumference will NEVER to exact but we make every effort to get very close and they are typically just a tad bigger. 
 
TO MEASURE:  Using a string, loosely wrap the string around the puppies/dog neck and mark where they connect.   Lay the string out and measure to the mark you made.  If at a 1/2" mark, size up.  
 
If you require something larger please contact me and I'll make it for you. &n