These collars are made from hard wearing woven nylon with a neoprene lining making them strong but also very comfortable.
Neoprene(wet suit material) is quick drying and also machine washable.
 
XS - 20-30cm
XS/S - 25-35cm
S/M - 30-45cm
M/L - 40-55cm
L/XL - 50-65cm