[Click to enlarge] 1-1/2" steel case Brass stem, 1/8" center back Easy to read color-coded gauge to ensure proper servicing. PART NUMBER BY-PASS SETTING APPLICATION P77-7003 0-60 color coded, 15 PSI indication Pressure P77-7004 0-60 color coded, 25 PSI indication Pressure P77-7021 0-30" Hg Vacuum