Select the wattage of your conventional bulb to find the LED equivalent.
Cap / Base
The cap/base of a bulb is the part that connects it to the socket in the fixture. In the UK, B22 (Bayonet) caps/bases are still the most popular, although E27 (Edison screw) caps/bases are becoming increasingly popular. GU10 is the most common cap/base for spotlights. Check which cap/base you need carefully as many other types are also available.
The colour code is a combination of the colour rendering index (CRI) and the colour temperature (K). The first number refers to the CRI (1 = very poor colour rendering, 9 = maximum accuracy). The second and third numbers refer to the colour temperature. For example, a light with a colour code of 830 has very good colour rendering and produces a warm white light.
Ballast is a term that designates a device to reduce the electrical current, it allows for example to power your source in 12V with a native voltage of 220V. There are two types of ballasts: ferromagnetic (or conventional) ballast and electronic ballast. The ferromagnetic ballast requires a starter made unnecessary for an electronic ballast.
Colour temperature (Kelvin)
The colour temperature refers to the colour produced by a light. It's measured in Kelvin (K) and ranges from warm white (1700K - 3000K) to daylight white (6500K). Neutral white (3100K - 5000K) is mainly used for general lighting applications.