The RTTS circulating valve is a locked-open/locked-closed valve that serves as both a circulating valve and bypass. The clearance between the RTTS packer (or any hook wall packer) and the casing ID is relatively small. To reduce the effect of fluid-swabbing action when the tool is run in or pulled out of the hole, a packer bypass is generally used.Features and Benefits：The valve can be locked closed when the packer is unset to reverse fluid around the bottom of the packer；The tool’s full opening allows tubing-type guns and other wireline equipment to pass.