My husband has tried various other brands of socks ,none of which
remotely resembled the L/XL I chose for him.
He finds Posey socks comfortable and true to advertised sizing.

HEIGHT ADJUSTMENT KIT, Configura comfort, 25mm
The Configura Comfort 1&2 Height Adjustment Kit increases the seat height by 1 inch. When the adjustment kit is being used the castors are raised off the ground.
25mm / 1 inch