Oakton's TDS Tester 11+ offers one-point push-button calibration and is waterproof and dustproof. Replaces TDSTester Pure+ (WD-35661-05), TDSTester Low+ (WD-35661-16), and the TDSTester High+ (WD-35661-26), making all three separate scales selectable in one portable large display tester. Use these testers for either cup-style or dip-style measurements. For cup style, pour a small amount of your sample directly into the sensor cup until it overflows; for dip style, simply immerse tester tip into sample. Replaceable sensor lets you reuse meter body many times over. Valox housing and stainless steel electrodes for good chemical compatibility.