crank shorteners

Anybody ever try these? They sound like possible alternative to adjustable crank arms.

Scroll down about half way.
Here’s a better picture.

Looks interesting. I wonder how well they work.

EDIT: The one big disadvantage is that you need to remove it to use your cranks at their longest length.

They look interesting and strong, but wouldn’t the excess length clip your ankles.

You’d definitely want to wear shorts. I think you’d be able to ride with the excess. You would probably need to be aware of them, and you probably wouldn’t be able to do lots of tricks…err skills with them on.