This is a Biothane^® collar with 3 width options. 3/4in wide is a single layer. 1in wide is a 3/4in main strap and 1in back layer. 1.5in wide is a 3/4in main strap and a 1.5in back layer. 

Standard Weight vs Heavy Weight Biothane®: Standard weight has more overlap behind the stones and may be more prone to scratching the skin or catching on fur. Alternately the heavy weight Biothane® is more stiff and harder to buckle when used with 3/4in buckles. If you would like to avoid these issues, I recommend getting a dual layer collar instead of single layer.

NOTE, choosing one stone color scheme works best on these due to the limited stones in the design.