Abstract: An air conveyor for gas test tubes used in the detection of foreign gases or suspended matter in air having an instrument body in the form of a handle and including a channel therethrough. The body has at one end a sealing element for connecting the gas test tube to the channel and at its other end a suction element in the form of a bellows. A base plate is included to which the suction element is mounted and has an air outlet valve therethrough and in communication with the bellows. A counter ring means is mounted to and rotatable about said body and including a spring biased locking element. A control rod is connected to the base plate and positioned for guided movement in the channel, said control rod being arrestable when said suction element is empty and releasable to initiate a suction stroke of said suction element by rotation of such counter ring.