The tray lifts off, which turns an infant scale into a bathroom scale - the same platform reads from 0.1 lb up to 330 lbs, so it keeps working long after a baby stops lying still for it. Resolution is 0.01 lb. A companion app records weight, height, head circumference and BMI over time rather than leaving it to a notebook and a pen. The tray measures 29 x 10.5 in with a raised edge. ABS at 4 lbs, the platform itself 12.5 x 11 in. White, with a user guide in the box.