Original Robertshaw Thermostat Oven Gas Control Knob with 'D' Adapter. There are no cracks or stains. This oven knob is bright & shiny, the lettering is all in great condition - the top cap is in very nice condition. The 'D' adapter allows it to be used with the original vintage Robertshaw Thermostats 'BJWA, 'BJ' for 'D' stem applications.