SEAL Team SIX pioneered the use of Free Fall to jump boats and other large operational gear. They perfected the method of High Altitude / Low Opening (HALO) jumping from upwards to 36,000 feet on oxygen. At that altitude the temperature is subzero, and it is common for your goggles to freeze and shatter, and your eyeballs to freeze shut. This type of jumping is very dangerous because of the effects of hypoxia - lack of oxygen. Hypoxia can cause a man to lose consciousness in an instance with no prior warning. One second you are checking your altimeter, the next you are out, bam - no warning. If this happens while in freefall it can lead to sudden deceleration trauma - you guessed it - death upon impact. Ecuipment common to all freefall ops are the Ram Air, altimeter, FF2 (automatic pressure activated rip cord pulling device - it is supposed to pop your chute if you don't when you descend past a pre-set altitude), hook knife, helmet and goggles, gloves, oxygen bottle and mask (if jumping over 12,000 feet) and a sturdy pair of jump boots are a must for ankle support.
