Polylab Kipp's Apparatus made of polyethylene has three main portions. The top portion is fitted with a thistle funnel and a bulb structure through which dilute acid can be poured which reacts with a metal sulphide in the base of the apparatus. H₂S gas then evolved colletcs in the middle dome from where it can be released through a leakproof stopcock fitted with a self lubricating PTEE plug. The base is provided with a residual outlet fitted with a cap for easy cleaning.