The first sit harnesses were basically a belt and leg loops made out of webbing, like alpine harnesses today and the Whillans harness of yesterday.
Then to this was added padding for comfort, an array of metal buckles for adjustment, multiple gear loops, rear elastic loops that join the leg loops to the waist belt and in some cases a haul line loops.
Harnesses got bulky and complicated, and sometimes just darn uncomfortable. Now most manufacturers make stripped down lightweight harnesses.
Mick Ryan takes the C.A.M.P Air harness, a featherweight at 233 grams, about 8 ounces, for a test.