Yes, but lighter than the same thing made out of metal! ha ha. Hope they work out well for you, they've gotten me (and my friends) out of a lot of sticky situations!
I just found out I'm moving to Japan in a few months so I'm hoping to get rid of some more of these before I go. New prices are:
Size Load (when supported on ends) Price
80 (1/4)" x 18 (1/4)" x 2" 1700 $250
80 (1/4)" x 10 (1/4)" x 2" 1000 $240
62 (1/4)" x 10 (1/4)" x 2" 1800 $200
38 (1/4)" x 8 (1/4)" x 2" 4200 $70