Just thought I’d throw in my two cents about the new LH350 helmet as we just bought 2 of them. I have had a HGU55 helmet for the last 13 years and love it. (I know it’s not an approved helmet for helicopters)
I took four helmets from work and compared them to each other, size and weight wise and this is what I came up with. This is what each helmet was installed with;
LH250 (large Shell) Dual Visor/Night Vision Attachment/Zeta Liner/Carbon Visor Cover
LH350 (Medium Shell) Dual Visor/Night Vision Attachment/Zeta Liner/Active Noise Reduction (w/Helmet Mounted 9V Battery)/NVG Lip Light/Volume Control
LH350 (Large Shell) Dual Visor/Night Vision Attachment/Zeta Liner/Active Noise Reduction (w/Helmet Mounted 9V Battery)/NVG Lip Light/Volume Control
HGU55 (Custom Fit) Single Visor/Oxygen Attachment
Model - Weight (Grams) - W x H x L(inches)
HGU55 (C Fit) - 1192 - 10.55 X 9.38 X 8.75
LH250 (L Shell) - 1528 - 10.75 X 10.55 X 10.85
LH350 (M Shell) - 1587 - 11.50 X 8.75 X 11.65
LH350 (L Shell) - 1778 - 12.20 X 9.25 X 12.35
I was lucky enough to fit into the LH350 Medium Shell, My head measured 22.8 inches, which is at the very high end of the Medium size helmet. The company I bought it from even tried to convince me to go to the Large size but after seeing the difference in the outer shell sizes I still wanted to try it. And I’m very glad I did as you can see by the measurements above. Although it is slightly heavier than the LH250 you have to remember my 350 has a lot more extras than the 250 we weighed, without the extras it would be a lot lighter.
The Two biggest concerns for myself was weight and height. As Im 6'2" i need all the head clearance I can get in the cockpit. As for the weight, its heavier than my HGU55 but loaded with all the options. Comfort wise the 350 is great, after a little customizing of the Zeta liner and ANR placement it fits just as comfortable as my HGU55 Custom Mold Helmet.
That’s my two cents, hope that helps some prospective buyers out.