This nice collar is 1" wide, attaches in the back with a 1" roller buckle and keeper, and, includes a "D" ring in the back. The spikes are 1/2 inch long and are VERY sharp.

The "small" size fits necks 12" to 14 1/2".

The "medium" size fits necks 14" to 16 1/2".

The "large" size fits necks 16" to 18 1/2".

The "extra large" size fits necks 17 1/2" to 20".