A catalyst return apparatus is disclosed as well as a riser reactor system comprising the conduit apparatus and a riser reactor, the conduit apparatus comprising a catalyst return conduit and at least two flow control devices in series, each flow control device arranged to control the flow of fluid through the conduit, wherein the length of the catalyst return conduit is more than 20 m. The device comprises an elongated member having an internal cavity and pressure-sensitive region. The changing visual content may be manipulated based on available resources associated with presenting the changing visual content as an overlay for a client.