It should apply to the following vests:
The following size chart applies to all Tipperary Helmets.
How to Measure:
Using a measuring tape marked in centimeters, measure around the widest part of your head. Make sure the tape measure is level and sits just above your ears, around the bump at the back of your head and above your eyebrows. A properly fitted helmet will make your eyebrows move when you rock it back and forth and should be snug enough to stay on your head without the harness.