These feet are very close to the original Naim ones you are replacing and are 10mm high x 20mm wide and rounded at the base of the foot. Nac 102 Olive. Nap 180 Olive. Nap 250 Olive. Hi Cap Olive. The recessed area of the foot is 7mm wide for the screw head and the hole for the threaded part of the screw is 4mm.
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