A load handling device for use in a storage system comprising a grid frame containing a plurality of stacks of containers, the load handling device configured for being arranged above the stacks of containers and the load handling device being capable of lifting a container from a stack and moving the container laterally to another location, wherein the load handling device comprises two sets of wheels (116, 118) for supporting the load handling device on rails, disposed above the frame, above the stacks, the two sets of wheels comprising a first set of wheels for engaging with a first set of rails to guide movement of the device in a first-direction, the first set of wheels comprising two pairs of wheels, and a second set of wheels for engaging with a second set of rails to guide movement of the device in a second direction, the second set of wheels comprising two pairs of wheels, wherein one or both sets of wheels (116, 118) are configured to be raised and lowered with respect to the other set of wheels (116, 118), characterised in that the load handling device includes a container-receiving space into which the container can be lifted such that the load of the container is suspended between the pairs of wheels on each side of the load handling device, and the container-receiving space is arranged beneath a vehicle module in which components such as power components, control components, drive components and lifting components are housed, and wherein the vehicle module houses a battery to power motors, controllers, sensors and other components. the load handling device configured for being arranged above the stacks of containers and the load handling device being capable of lifting a container from a stack and moving the container laterally to another location, wherein the load handling device comprises two sets of wheels (116, 118) for supporting the load handling device on rails, disposed above the frame, above the stacks, the two sets of wheels comprising a first set of wheels for engaging with a first set of rails to guide movement of the device in a first-direction, the first set of wheels comprising two pairs of wheels, and a second set of wheels for engaging with a second set of rails to guide movement of the device in a second direction, the second set of wheels comprising two pairs of wheels, a first set of wheels for engaging with a first set of rails to guide movement of the device in a first-direction, the first set of wheels comprising two pairs of wheels, and a second set of wheels for engaging with a second set of rails to guide movement of the device in a second direction, the second set of wheels comprising two pairs of wheels, wherein one or both sets of wheels (116, 118) are configured to be raised and lowered with respect to the other set of wheels (116, 118), characterised in that the load handling device includes a container-receiving space into which the container can be lifted such that the load of the container is suspended between the pairs of wheels on each side of the load handling device, and the container-receiving space is arranged beneath a vehicle module in which components such as power components, control components, drive components and lifting components are housed, and wherein the vehicle module houses a battery to power motors, controllers, sensors and other components.