That shady character on the corner just sold you a plastic skull keychain with fiery orange eyes. He assured you it weighed 25 grams, but how do you know you're not being ripped off? Fortunately, Brando has come out with a USB optical mouse that has a built-in digital scale, designed, apparently, for this precise situation. Just lift up the cover, calibrate the reader and weigh away. Pencils, lint, small animals -- the list of measurable items is endless, as long as your goods don't exceed 500 grams. To get the good times rolling, hit the source link, where you can grab one for $22.