Size Guide: For Dog Chain Collars, Measure The Circumference Of Dogs Neck And Add 2''. Please Measure The Length Of Neck Before Ordering.

Size Reference: 2.0 Mm Thickness, 12'' Length, Suitable For Neck 9''To 10'' 2.0 Mm Thickness, 14'' Length, Suitable For Neck 11''To 12'' 2.0 Mm Thickness, 16'' Length, Suitable For Neck 13''To 14'' 2.5 Mm Thickness, 16''Length, Suitable For Neck 13'' To 14'' 2.5 Mm Thickness, 18''Length, Suitable For Neck 15'' To 16'' 2.5 Mm Thickness, 20''Length, Suitable For Neck 17'' To 18'' 3.0 Mm Thickness, 18''Length, Suitable For Neck 15'' To 16'' 3.0 Mm Thickness, 22''Length, Suitable For Neck 19'' To 20'' 3.0 Mm Thickness, 24''Length, Suitable For Neck 21'' To 22'' 3.5 Mm Thickness, 20''Length, Suitable For Neck 17'' To 18'' 3.5 Mm Thickness, 22''Length, Suitable For Neck 19'' To 20'' 4.0 Mm Thickness, 20''Length, Suitable For Neck 17'' To 18'' 4.0 Mm Thickness, 22''Length, Suitable For Neck 19'' To 20'' 4.0 Mm Thickness, 24''Length, Suitable For Neck 21'' To 22'' 4.0 Mm Thickness, 26''Length, Suitable For Neck 23'' To 24'' 4.0 Mm Thickness, 28''Length, Suitable For Neck 25'' To 26'' 4.0 Mm Thickness, 30''Length, Suitable For Neck 27'' To 28'' 4.0 Mm Thickness, 31''Length, Suitable For Neck 28'' To 29'' Leash Attachment: O-Ring Attachment, Easy On And Put Off.

The Diameter Of This Collar Is 2.0 Mm, Which Is A Bit Thin. Please Consider Carefully Before Ordering.