Originally Posted by sers
removable "beams" that run through the center of the sole that can be slid out from the back of the heel and thrown in your bag when you want more flexibility in the sole.
i remember there was a shoe made by nike (i think) that had
a removable insert for the outer sole that could be exchanged
for a harder or softer heal.
an interchangable plate, as suggested by enlacalle, would be ideal.
(now puma just needs to step in...)