The Ring Seal Floating Packer is a simple and low cost sealing device for use in steam injection wells and is proven to be an effective mechanical device for controlling and blocking the passage of fluids in an annular space between the tubing and casing. The Ring Seal Packer can be compared to a piston in a cylinder: Pressure forces acting upon a piston result in up and down motion while the piston maintains a seal against the cylinder (casing) wall. Compared to a conventional thermal packer, the Ring Seal Packer does not require an expansion joint allowing the injection tubing to thermally expand and contract while the Ring Seal Packer moves up and down the casing maintaining its sealing ability. This paper covers the following areas: Mechanical DesignLaboratory testing providing loading confirmation for deployment.Field results at PEMEX Samaria oil field, Mexico, Cyclic Steam Stimulation (CSS)California field results of CSS into vertical wells with multiple zones above and below the RSP.Field results at Mansarovar, Colombia.ConclusionReferences