Abstract: An apparatus for sequentially performing multiple downhole functions in a well has tubing arranged to transmit pressure conditions from the surface of the well, upper and lower hydraulically activated firing heads suspended within the well on the lower end of the tubing, and a hydraulically responsive movable member between the tubing and the firing heads. Each firing head is configured to detonate an associated tool in response to an associated elevated tubing pressure condition. The movable member transmits a first elevated pressure condition to activate one of the firing heads, and moves in response to a subsequent elevated pressure condition to activate the other firing head. In one embodiment, the movable member has a through passage for transmitting the first elevated pressure condition, the passage being subsequently blocked by a ball dropped through the tubing to move the member in response to the second elevated tubing pressure condition.