Apollo 3.0 Double Kit - Radiometer/photometer measuring UV and visible light via a wireless sensor. Apollo 2.0 is traceable to NIST (National Institute of Standards and Technology) and is in compliance with ISO 3059-12. Comes calibrated by an ISO / IEO 17025 calibration lab with scope in UV and WH calibrations. The double kit comes with 2 sensor units so that you do not disrupt your operations – send only one sensor at a time for calibration.