ORP Sensor, Industrial Pool and Spa Water Chemical Controller Probe, Acu-Trol Compatible, Platinum Band MEASURES OXIDIZING ABILITY OF CHLORINE - The PoolWarden Oxidation-Reduction Potential (ORP) Sensor measures the chlorine's oxidizing/reducing ability in your spa water or swimming pool. MADE WITH PREMIUM MATERIALS - This industrial ORP sensor features platinum tip with 1/2-inch NPT standard thread. Plus, PoolWarden offers electrodes with color-coded caps for easier sensor identification (e.g., red for ORP and blue for pH sensor). ENSURES FREE FROM LEAKS - The standard 1/2" NPT (national pipe tapered) thread makes a closer seal compared to straight threads. OFFERS LONGER LIFE - The double junction construction ensures the PoolWarden ORP Sensor lasts longer compared to its competitors. COMPATIBILITY - Replaces the ORP sensor for Acu-Trol AK110, AK2100, AK600, and ControlOMatic PoolWarden.