Does the job OK under a treadmill. But on thicker carpet, it easily bunches up and has large dents under the feet of the machine. There should be an option for an extra thick/stiff floor mat. This particular mat would be best on hard floors or commercial-type non-padded carpet
The mat serves well under the bike. The weight of the bike would easily make permanent impressions in the carpet without the mat. It also helps stabilize the bike.
I love my mini stepper with handle bar! I started out doing 10 steps, then 20, now I can do 100 at a time, doing 1,000 steps a day. I love the small footprint. It's so convenient to hop on and whip out 100 steps.