2-Pack Contains 2 Individual Packages: Reliable and Accurate Induction Probe Ensures Accurate and Instant Test Results for Indoor or Outdoor Use. Easy to read: large dial, including ten scales, plug and read. HOW TO USE -- No batteries required, use indoors or outdoors. Simply insert the probe about 3-4 inches into the soil and you will be able to get a reading. Ideal tool for indoor/outdoor plants, help your plants grow healthy and strong. Less damage: single probe, less damage to the roots, not digging out too much soil after the test. Important Tips--1, Don't use it to test water. Do not touch stones or hard rocky soil, if the soil is too hard and dry, it is easy to damage the probe. 2. Never use it to test liquids. Designed for testing soil only. 3. Please wipe the probe clean after use.