Abstract: A single-piece adapter (10) is disclosed for supplying gas to a gas detector (32) that contains at least one gas sensor (34) and that has a gas inlet (30) for allowing gas at the inlet to come into contact with the at least one sensor (34), which adapter comprises: a chamber (24) having an opening formed by a rim (22) for fitting over the gas inlet of a gas detector (32), the chamber having an inner surface (18), an inlet duct (14) for feeding gas into the chamber in a direction transverse to the opening, and an outlet (16) to vent gases from within the chamber. The inner surface (18) of the chamber is formed by a first moulding (12) of a rigid, non-absorbent material and a second moulding (20) of resilient material. The second moulding forms the rim (22) for providing a gas-tight seal between the adapter (10) and the detector (32).