Abstract: A stack support tray 41 for use with a sheet feeder such as used in a document handler is described. It has a first fixed registration guide 52 and a second movable registration guide 53 which is movable towards and away from the first guide. The movable guide 53 comprises first and second resiliently interconnected parts 71, 72. The part 72 frictionally slides in a track 75 and the second part 71 is adjustable against the stack. By this arrangement the part 71 retracts to a limited extent when it is released after being pushed against the stack due to its resilient interconnection with the part 72, the position of which is controlled by its frictional engagement with the slide track 75.