An autonomous transport vehicle for a storage and retrieval system, the autonomous transport vehicle comprising: a frame forming a payload area; telescoping arms (802A, 802B) movably mounted to the frame, each telescoping arm (802A, 802B) being configured for extension and retraction relative to the frame along an extension axis to effect transfer of at least one pickface to and from the payload area, and traversal, relative to the frame in at least one direction (297, 298) that is angled to the extension axis; and at least one tab extending from each telescoping arm (802A, 802B) where the at least one tab extends in a direction transverse to the direction of extension and retraction, and the at least one tab on one of the telescoping arms (802A, 802B) opposes the at least one tab on the other one of the telescoping arms (802A, 802B); wherein each telescoping arm includes a free end and a rotatable finger mounted to the free end, the rotatable finger being movable between a retracted position so as not to contact the at least one pickface and a deployed position so at to engage a vertical side of the at least one pickface and effect at least transfer of the at least one pickface into the payload area, characterized in that each telescoping arm includes a movable pusher member that opposes the rotatable finger, the movable pusher member being configured to linearly move towards and away from the rotatable finger to at least clamp and release the pickface between the movable pusher member, and rotatable finger. a frame forming a payload area; telescoping arms (802A, 802B) movably mounted to the frame, each telescoping arm (802A, 802B) being configured for extension and retraction relative to the frame along an extension axis to effect transfer of at least one pickface to and from the payload area, and traversal, relative to the frame in at least one direction (297, 298) that is angled to the extension axis; and extension and retraction relative to the frame along an extension axis to effect transfer of at least one pickface to and from the payload area, and traversal, relative to the frame in at least one direction (297, 298) that is angled to the extension axis; and at least one tab extending from each telescoping arm (802A, 802B) where the at least one tab extends in a direction transverse to the direction of extension and retraction, and the at least one tab on one of the telescoping arms (802A, 802B) opposes the at least one tab on the other one of the telescoping arms (802A, 802B); wherein each telescoping arm includes a free end and a rotatable finger mounted to the free end, the rotatable finger being movable between a retracted position so as not to contact the at least one pickface and a deployed position so at to engage a vertical side of the at least one pickface and effect at least transfer of the at least one pickface into the payload area, characterized in that each telescoping arm includes a movable pusher member that opposes the rotatable finger, the movable pusher member being configured to linearly move towards and away from the rotatable finger to at least clamp and release the pickface between the movable pusher member, and rotatable finger.