Built to agree with our master instruments, which are traceable to the United States National institute of Standards and Technology. It complies with AAMI SP-9 for accuracy and performance (1% full scale ± 3 mm Hg). Its unique high contrast scale and red pointer increase visibility and reduce parallax error. The manometer is manufactured with a metal mounting bracket, high impact ABS plastic manometer housing, precision low-friction movement and twin preseasoned phosphor-bronze diaphragm capsules.