The LPR-N? tester valve is a full-opening, annulus pressure-operated valve. It measures multiple closed-in pressures in cased holes where pipe manipulation is restricted and a full-opening string is required. The nitrogen chamber is charged at the surface to a selected pressure determined by surface temperature, bottomhole temperature, and bottomhole pressure. If the intended test requires a permanent packer that uses a stinger mandrel or seal nipple, a variety of Halliburton bypass tools are available, depending on field application, to help ensure that the formations and downhole equipment are protected from excessive pressure buildup.