Petromax 829, stamped 0722 on bottom of tank, believed to be 1962 production. On stripping the NRV assembly a shorter model than usual was found to be fitted. This was replaced with a standard Petromax NRV assembly. Short NRV as found fitted: Standard NRV top, Short NRV below: A standard Petromax NRV was fitted during the refurbishment. No problems were encountered with fitting the new standard NRV.