My advice is not to get Index, Zeus, THH full face helmets.
Although they are cheap, they are poor in build, safety &
quality. Get the following(see to suit your budget) :
1. Nolan ($200+) (Ah Boy)
2. HJC ($150 - $220+)(MotoWorld)
3. OGK ($350 - $450+) (Ah Boy)
4. Arai/Shoei ($380 & above)
5. AGV ($500 ++) (MotoWorld) (V. Rossi replica)
6. Shark (MotoWorld)