As skills and equipment improved, the maximum measurement decreased and today we use 16 cms. Also the Dead Center Disc went from 10cm , to 5cm , then 3cm to today’s 2 cm yellow on a black background disc. We also have an electronic recording pad which measures in 1 cm increments up to 16cm. This sits in the middle of a tuffet . A tuffet can either be a deep foam mattress or an air-filled landing pad – similar to that used in pole-vaulting, or high jump.