Handmade Leather O-Ring Collar

This handmade leather collar has one central O-Ring as well as three more nested inside each other hanging from the base of the collar. This can be adjusted to fit from 33cm to 38cm so will fit a slimmer neck. 
The length at the front is 13.5cm; if including the rings it’s 18cm. 
The rings are solid steel. The smallest measures 33mm internal diameter, 44mm external diameter. The middle size measures 37mm internally, and 50mm external diameter; with the largest ring measuring 52mm internal diameter, and 65mm external diameter.