Not very thick - so after a few hours of sitting the wheels of the chair create indentations in the mat thus making it more difficult to roll the chair - i'm average weight of 160 pounds too...
I like the chair mat I purchased from Staples in that it protects the carpeting my chair with rollers sits on. No more tattered carpet fibers. I will most definitely purchase one for my wood floors. Thank you!!
Any time you have a chair that rolls on carpet numerous times you need this type of mat. Not only does it make the chair easier to move but it save your carpet from excessive wear.