Scoop

Resembles a long board or stretcher, but is adjustable at one end so you can measure the scoop to the individual's length. Has clips at the top and bottom so the entire thing can be halved, with each half being placed on either side of the person. Each half is then slid beneath the individual and the scoop is re-clipped, so it is now whole again and fully supportive of the casualty.
It's generally not used for transporting a casualty (with us anyway), but for transferring a casualty from the floor to a long board when log rolling is not appropriate. Scooping is easier anyway really. Unless the clips are gritty.