These Loc Fast collars twist to tighten on a 1” standard barbell. Made in the USA by Billard Barbell, they are actually for a barbell slightly larger than 1”. They work best on a standard barbell slightly just a little thicker. They’re also just a cool vintage pair of collars, because they’re an early version of a design now made by several companies. They’re in excellent usable condition.

This particular pair are the larger, heavier version labeled Mansfield, PA. They have ridges on the sides.

I have two other versions of these collars listed!