I bought a cheap handheld body-fat % calculator from wal-mart for $13...i workout or run everyday?

and i have detailed abs and absolutely no visible fat on my body.....however, when i use it it tells me my body-fat% is 26%!? i'm 180 5'11" and have no pudge on my belly or anywhere else at all. i also used it on my roomate who is overweight and it returned nearly the exact same reading? is this thing a piece of crap or what? i just don't get it, i've only been called skinny in my life and this thing tells me i'm overweight and full of fat...it's depressing as hell :(