Humidity beads are silica-based (essentially sand and air) materials designed to maintain a constant humidity. Essentially, they absorb and release moisture to and from the air in your humidor to maintain a consistent humidity level. They are designed to require very little work to achieve the ideal conditions for storage of cigars. One of the main advantages of humidor beads is that it is nearly impossible to over-humidify your smokes.
Measure your humidor's length, width and height, then multiply those numbers. You now know the volume of your humidor. It takes approximately one ounce of beads to regulate five hundred cubic inches of space. It is impossible to over-humidify with humidor beads, but if you do not have enough beads, you can under-humidify, so round your volume calculations up.
Soak the humidor beads in distilled water to recharge them when they become dry. Use a syringe to drop the water evenly over the beads or a misting spray bottle to moisten them thoroughly.
Add more beads if necessary for your humidor. You can't have too many, so if your humidity gauge is showing levels that are too low, buy some more beads for your cigars.