I'm so out of the loop. I thought the OP was looking for an alternative to either Shoei or Arai helmets. At least I knew it wasn't @motion looking for an old stinky vag.
Anti-Gravity swapped from race bike to KLX to EXC-F - worked great in all and still going after 5 years.
So a related battery question. Does anyone make a 6V LiFePO battery that has enough juice to crank a small twin (200cc)? I can easily find small 6V batteries that will work for bikes that are kick-only and just want a battery to help level things out, but I have one project bike that would be great to have a small battery that can be stashed on its side. I haven't been able to find anything with enough juice though, and I don't trust myself to build my own.
Contact Full Spectrum. I'm sure they could sort you out if you give them what you're looking for in regards to power demands and physical dimensions.