JoshWise
New
All regulators are compatible with Nitrox up to 40% O2. Manufacturers would like you to buy a second special reg but it is not necessary. Above 40% the reg must have O2 compatible o-rings and lubricant. Some regs come ready for 100% O2 out of the box but not many as most use rubber o-rings and rubber and high O2 don't get along. A nitrox class should cover all this in detail.
It's not rubber its the type of rubber used in the o-ring as well as the silicone grease that is used.