Mechanical Design Corporation is a manufacturer of Pipe Test Plugs and Joint Testers. They specialize in engineering custom solutions in standard and non-standard sizes, low and high pressure and unusual applications and have worked with various large companies including but not limited to General Electric, Exxon Mobil, Shell, Oceaneering, and Westinghouse. Products offered include Pipe Test Plugs, Joint Testers, Double Block & Bleed Plugs, Flange Weld Testers, Bypass Pipe Plug, Bulkheads, Foreign Material Exclusion Plugs/Caps/Covers, Nuclear Plugs, Mechanical Plugs, Fail-safe Plugs, Underwater Plugs, Remotely Installed Plugs, Diver Installed Plugs, ROV Installed Plugs, Split Sectional Plugs, Square or Irregular Shaped Plugs, Steam Generator Plugs, Reactor Nozzle Plugs, Hot and Cold Leg Plugs, Annular Seals.