With a light output equivalent to a 50W incandescent GLS but a power consumption of just 42W, these halogen Lightbulbs Directly replace existing GLS light bulbs to save 30% of your electricity costs.These light bulbs also have an increased life of 2000 hrs and on top give out significantly reduced heat and is a cost effective version of a CFL.Features a BC-B22d bayonet (22mm) cap base. Also known as an A55 light bulb.Need more help in choosing a suitable light bulb? Read our guide What is a GLS Light Bulb.