Halogen lamps come with a variety of bases, some of which are common to both incandescent and halogen lamps. Some are single built-in and/or Bi-pin and are particular to halogen lamps and infrared quartz. They are usually made of steatite or heat resistant metal. Double-ended type halogen lamps feature a plug-in and out RSC base. Lead wire type is becoming more and more popular for use in certain heater lamps because of connection reliability. When identifying halogen lamps these designations are the ones known in the industry.