A load handling device is disclosed for retrieving, transporting, and delivering containers in a storage system having a grid structure formed of two substantially perpendicular sets of rails or tracks located above stacks of containers. An exemplary load handling device can include a wheel assembly, a container receiving space, and a plurality of vehicle modules. The wheel assembly can include a first set of wheels to guide movement of the load handing device in a first direction and a second set of wheels to guide movement of the load handing device in a second direction. Each of the vehicle modules can include a container lifting means arranged to lift a container into the container receiving space and each of the vehicle modules can be moveable to adjust the spacing of the containers in the load handling device.