a thick rubber instability mat, measuring 16'' by 20''? And if you know what it is, could you tell me where to buy it? i have been looking online and at stores and I can NOT find it...

Please let me know

It sounds like what you put in your shower to keep from slipping,especially if you have a shower over your bath tub.

well this one is pretty thick, kind of like a yoga brick but bigger? The doctor from the Biggest Loser designed a program using it, but i cannot find it...

Thanks for your answer though

Anyone?

Are you sure it's not a "stability" mat and not "unstability"?
A stability mat could be like a yoga mat or the thick ones that go under treadmills. Do you have a link or anything to the program that uses it?
I've seen several kinds of mats at Walmart.

i found a picture on-line:
http://www.greatmats.com/products/airex/corona.php

It is what the couple is standing on, the little square blue thingy. Anyone knows the name or where I could purchase it?