We'd all love to go racing in jeans and a T shirt, but we can't! Most forms of racing insist we wear at least a 2 layer race suit, some underwear as well to give a total of 3 layers of Nomex or a combination of Nomex, Delta C and or Lenzing. We'd always recommend a three layer suit, but in many countries of the World, the temperature has a huge effect on the crew and a lighter 2 layer suit is a welcome option. Fireproof underwear is always recommended as it's worn close fitting and in any fire filled cockpit that inner layer, predominantly in contact with the skin can make all the difference, especially your Nomex balaclava and socks as not everyone wears Nomex lined 8856-2000 homologated race boots. Ensure all your racewear is FIA 8856-2000 approved and you'll be welcomed by the scrutineers, there's no running out date yet for this approval number and the manufacture date is irrelevant, unlike kart wear which does have a 5 year life on kart suits.