An optical sensor accurately records the number of drops of titrant added during a titration. This sensor, along with a temperature or pH probe, will record pH and temperature values and calculate the first and second derivatives of the pH for easy equivalence point determination. The Drop Counter Sensor can also be used as a utility clamp any time an electrode needs to be held into place. It can also be used with your own buret or with the included reagent reservoir—designed to keep the drop size consistent. Includes a microstirrer, which when attached to a pH probe and used with any magnetic stirring plate, provides faster response after each drop is added. Digital sensor.