support pads 38 fig2 is an exploded view of the rack 10 of fig1 the support pads 38 can be separately molded pieces as shown that can be snap fit onto the upper section 22 an expandable inflatable clamping chamber 30 is mounted to the upper section 22 adjacent each bay 16 the expandable chambers 30 are elongated flexible pneumatic bladders or seals that extend from the front of the rack 10 to the rear of the rack 10 and curve back to the front of the rack 10 adjacent the adjacent bay 16 the expandable chambers 30 each include a flange 33 spaced from an integral expandable tubular portion 34 retainers 31 each include a pair of fingers 32 for locking between the flange 33 and the tubular portion 34 of the expandable chambers 30 to retain the expandable chambers 30 to the upper section 22 as shown in fig2 a the upper section 22 also includes a plurality of fingers 35 that protrude between the flange 33 and the tubular portion 34 of the expandable chamber 30 to retain it to the upper section 22 for installation the expandable chamber 30 is first routed on the upper section 22 fitting the flange 33 of the expandable chamber 30 behind the fingers 35 the retainers 31 are then installed first fitting the fingers in front of the flange 33 and then snap fitting the retainers 31 to the upper section 22 if the expandable chamber 30 ever needs to be replaced the retainers 31 can be removed to remove the expandable chamber 30 fig3 and 4 are top and bottom perspective views of the layer 12 respectively.