PPK-1 partial pressure suit, or "speed-jeans" - as this type of suits also known, was developed
sometime around 1970 and stayed in service until recently; in fact, it might still be used in some
of the units.
PPK-1U is an extremely simple design - there is a wide waist area with a bladder inside and two
leg parts with zippers for pilot to easier get into the pants. Each of the leg parts has a round
hole in the middle, where pilot's ankles located. Both upper and lower portions of the leg parts
have adjustment laces. During high G maneuvers, suit tightens lower torso and leg muscles to slow
down the flow of blood towards pilot's legs and inflated bladder fixates internal organs in place.
Combination of these two allows pilots to sustain higher G loads before starting to blackout.
Vympel, manufacturer of the suit, says that PPK-1 "speed-jeans" have a useful life of 10 years
since the date of production.
PPK-1 suits are available in sizes 1 through 5.