The GU10 is the most common type of spotlight bulb found in most homes today. It is otherwise known as a PAR16 light bulb and is often used in places where a bright, directional light is needed, such as kitchens and workspaces. It has the classic spotlight shape, with a narrow base that widens into a flat or slightly rounded aperture.
‘GU10’ refers to the type of fittings these light bulbs have. Two short, square-ish pins protrude from the base of the light bulb. Like the bayonet cap, this is a ‘push-and-twist’ type of fitting (although a GU10 spotlight bulb will not fit in a BC fitting and vice versa). Be careful not to confuse a GU10 spotlight bulb with an MR16 light bulb. The two look almost identical, except for the fittings, which are much smaller, needle-like pins on an MR16 and will not fit a GU10 lamp.
Energy-saving GU10 spotlights
Halogen GU10 spotlight bulbs are commonly made from plastic. An EU directive that took effect in 2016 has banned halogen GU10 spotlight bulbs from sale in the UK. However, there are a plethora of LED energy-saving alternatives available.
‘Long barrel’ GU10s are a variation on the typical GU10 spotlight and are designed for the non-standard light fixtures used by some furniture and home furnishings companies. Long-barrel GU10s are around 75mm in length, compared to 50-55mm for a standard GU10.
LED GU10 light bulbs have been designed to look like the halogen light bulbs they supersede. They have the classic GU10 shape and closely resemble their halogen counterparts, available in a range of colour temperatures and in both dimmable and non-dimmable varieties.
You can read more about LED dimming here.