Reid Pitman wrote an answer about Grivel Salamander Helmet on September 22, 2014
Hey Skylar, Sorry for the delayed response!
So the helmet I use now is a Petzl ecrin roc, I've had BD half dome, mammut skywalker, petzl meteor III. Recently tried on BD Vector and Vapor, the M/L fit ok but still very high.
My had is 61cm circumference and 11cm from brow to crown.
I've been using a Giro Feature and Smith Variant for mountaineering this year.