Abstract: A tool for running on a well string such as a drill string in a well bore carries inflatable packer means to close off the well bore adjacent the tool. The tool includes a body having a longitudinal bore therethrough with seating means and shock absorbing means for absorbing the shock of seating a bore close off means to close off the bore in the drill string. The bore close off means includes latch means for latching the bore close off means in seated position in the well string.The tool may be positioned in the drill string near the drilling bit and when pressure is applied in the well string at the earth's surface such pressure is conducted through the bore close off means to inflate the inflatable packer means and seal off the well bore beneath the inflated packer means.