Luster Leaf 1601 Rapitest Soil Tester, Test Kit for pH, N, P and K Quick, at home results for Soil pH, Nitrogen, Phosphrous and Potash Innovative and inexpensive soil test kit features an easy-to-use capsule system and patented color comparators Contains all components needed for 40 tests. 10 for each of pH, N, P and K Simple, detailed instructions included. Great for beginners and experienced gardeners alike. Soil pH preference list for over 450 plants included