Chromed and lipped bezel ring as used on Smiths (80mm diameter) chronometric Speedometers that would be mounted into binnacles and headlamp shells. The lip prevents the speedometer from dropping through the binnacle, and the speedometer is normally held in place by using a 'U' bracket from behind. I include a picture of my Royal Enfield Constellation which is fitted with an orignal 150mph Smiths speedo with a lippeed ring. This is a high quality, UK made item,