This collection of lamps are all GLS style low energy lamps and all BC (bayonet cap). Within this collection you will find a choice of wattages including, 7w, 9w, 11w, 15w and 20w. The energy saving bulbs in this collection can all be used as direct replacements for the standard GLS bulb and so will help you reduce energy costs and consumption. Make Haysom lighting your first choice when purchasing your BC energy saving GLS bulbs.