This space acts as a cushion of cool air between your skin and the heat from the flame. It takes about six seconds for the temperature of a flame to transfer through a one-layer suit. A two-layer suit gives you about 14 seconds. Gloves should be snug but comfortable when making a fist. Features to look for include two-layers of Nomex and Nomex under the palm.
Some gloves are even sewn inside-out so the seams are on the outside.
Although this is the most comfortable, it is the most expensive and the least durable. If you are racing a formula car you might want padding across the knuckles if they scrape the bodywork when you shift. You might also want a padded palm to prevent blisters from a vibrating wheel. Some gloves even have padding or extra leather around the thumb. Racing shoes not only protect you from fire, but also help prevent you from tripping over yourself in the tiny footwells of formula cars.