The Bluelab? Grower?s Toolbox combines the essential tools you need to easily manage your crop by measuring the pH, conductivity (ppm) and temperature of the nutrient solution. Learn the hydroponics basics with the Grow Book, so you can get going? And keep growing with the ultimate handy team, the Bluelab? pH Pen and Bluelab? ppm Pen. These clever little pens make it easy to measure the nutrient uptake (pH), the amount of food available (ppm) and the solution temperature, so you can create the best nutrient environment for your plants? growth. The Grower?s Toolbox is a complete simple crop management system that helps you get it right, from the start. Contents: pH Pen (AAA battery included), ppm Pen (AAA battery included), Bluelab Grow Book, Probe Care Kit – pH & Conductivity, Probe care instructions, 20ml Solution Sachets, (2 each of: pH 7.0 & pH 4.0, KCl, 2.77 EC), 3x plastic cups, pH Probe Cleaner, Conductivity Probe Cleaner, Toothbrush (pH probe cleaning instrument) and Chamois (conductivity probe cleaning instrument).