Bell, Paradox Pro 2000 All Mountain Bikes >>> Mountain Bikes by Bell More details and ordering info. When you head out riding, you always feel safer with a trusty lid strapped on your head. With 18 total vents and the most comfortable and easy to use fitting system on the market, you may forget you have it on. Bell - courage for your head. Small 21 1/4'-22 1/8' or 6 3/4-6 7 hat size, Medium 22 1/2'-23 1/2' or 7 1/8-7 3/8 hat size, Large 23 5/8'-24 3/8' or 7 1/2-7 3/4 hat size. User input on Paradox Pro 2000 by Bell: Be the first to submit input on this product Submit Input: Your Name: Write or Paste Input here: Upload picture:      Review Guidelines