Dresser Intervention Solutions Pressure Control and LineStop Fittings are compatible with specific tapping and plugging equipment and are designed to carry the extra loads imposed during hot tapping and line stopping operations.  Dresser offers a series of tapping machines to make pipe taps while pipeline is under pressure without interrupting service: The M4 Series (12-30 inches of travel); the compact M200 Series (30″ of travel), the M300 Series (42″-66″ of travel); and the M1248 Series (80″-120″ of travel).