This genuine leather collar has a single row of unique metal spikes. These spikes have six sides in the middle, just like a six sided screw. A solid metal buckle holds the collar in place. 3/4 inch wide, this collar is available in two sizes, small/medium and medium/large. - Width: 0.75 Inch - Small/Medium: Fits 13 to 16.5 inch neck - Medium/Large: Fits 15 to 19 inch neck