1" strap slider. While this slider is considered 1 inch the inside diameter is @23mm, nylon and cotton webbing fit just fine but thicker straps may not fit as well. You may want to make your straps a scant 1" size or do a trial sizing.
These are one of our original products, slight blemishes on the back are noticeable but doesn't effect the buckle. I have seen the blemished on the bar where the strap goes. It shows mostly on the gun metal ones.