The bulb of Osram Decostar 51S is a halogen bulb consists of a 51 mm reflector and a GU5.3 base. MR16 bulb. Its lifetime is 2000 hours with a very good light output. The bulb is dimmable and 51S has a UV filter. The OSRAM DECOSTAR 51S powers exist in 20W, 35W and 50W. Bulb quality.