Part Number : 05B50079520 (listed in Miralbueno catalogs as "Base RM52 PVC Neg SW MICST - Black" – "SW MICST" indicates integrated switch/microswitch for heating safety/thermostat). Molded high-density foam padding with ergonomic contouring (side bolsters for support, central recessed area with stitched pattern for comfort and grip).
eBay