The Power Block U90 Stage 3 add on kit requires U90 Stage 1 + 2 & replaces 34 pairs of dumbbells, or 1783kg (3930.8lbs) of free weights. It expands the U-90 up to 57kg (125.6lbs) per hand & is supplied with 2 additional weight plates & a taller handle set for use with additional weight plates. in addition, it is part of the Urethane series & is shipped in two boxes.