Micro Essential Labs 335 Hydrion Vaginal pH Testing Strip 4.5 - 8.5 (2210) (PH-335). This short-range Hydrion pH Paper is excellent for measuring pH solutions around neutral pH 7.00 and offers clear bright single color matches at every 0.5 interval from pH 4.5 - 8.5. Hydrion pH Paper is on a 15-foot roll provides for approximately 100 tests. 1RL/EA. Price per each.