Granville Phillips Stabilion 370 Stabil-Ion Gauge, Extended Range with Dual Yttria Coated Iridium Filaments 2.75 Inch Conflat-Type Flange and Calibration Memory Module. All metal gauge tube means no glass breakage, glass decomposition, or helium permeation. Complete electrostatic shield and grounded metal gauge tube housing provides a stable electrical environment and shields against external electrical influences. Burnout resistant filaments. Precision-wound, stress-relieved grid retains shape