Doulton Filter kits use advanced ceramic filter candles. 2 kits are available, either with the Supercarb candle or the Ultracarb candle. Both use the HIP plastic housing and come complete with our popular Duo tap which has both standard and long reach spouts, saddle valve and all necessary fittings and instructions. Simple push fit fittings are used throughout. Candles should be changed every 6 months.