The Versacal is a PSL calibration fluid insertion fixture for performing particle size verification tests on the Hach Model PCX or PCT on-line Drinking Water particle counters at their mounted locations; The small transparent drip chamber provides visual flow indication to set the particle injection rate by using the pinch valve's rotary adjustment knob; The chamber is equipped with a re-sealable injection port that allows a small volume of PSL calibration fluid to be injected and reside during the calibration check