Apogee MQ-500: Full-Spectrum Quantum Meter. Just the unit and sensor.
No guessing ppfd, just the hard stats to get the best parameters for your operation. Can't recommend this enough, better than any cheap guessing substitute tool. This item is in the category "Garden & Patio\Hydroponics\Grow Lighting & Accessories\Grow Light Kits".The seller is "thompatr-efkav3" and is located in this country: GB. This item can be shipped to United Kingdom.