150 watt, metal halide, single-ended, GY9.5 Bipin Prefocusbase The SIL 150 is a replacement for Osram’s HTI 150. This bulb is used primarily in effect lighting, stage & studio lighting, and commercial projection lighting. Bulbamerica"s ATI 150w is a high performing and inexpensive replacement for the HTI 150, so check it out today.