Continue to protect your investment with replacement packets for the D?Addario Two-Way Humidification System. These packets are now available in bulk 12-packs that offer a 10% cost savings and are perfect for luthiers and guitar repair shops! The D'Addario system is the only maintenance free, two-way humidity system for guitars. By adding or removing moisture on demand the Humidification Control System automatically maintains the optimal 45-50% relative humidity level within a sealed environment (your instrument case) - the ideal climate for wooden instruments. The technology behind this product eliminates humidity concerns regarding seasonal changes, geographic location, temperature, or other factors without any guesswork or mess from refilling the humidifier. It is essential to humidify all wooden instruments. Lack of humidity can cause warping, cracks and other serious damage. The D?Addario Two-Way Humidification System packets last 2-6 months. Once they become firm, you simply discard and replace with new packets. No water, no drips, no mess, nothing to maintain. Replacing the packets in the Two-Way Humidification System is a necessity to maintain the stability and playability of your instrument. For over 20 years, D?Addario has been leading the industry in innovative and problem-solving products that serve musicians worldwide. D?Addario Accessories are proudly made in a state-of-the-art manufacturing facility in the USA to the most stringent quality controls in the industry. The D?Addario family?s heart, soul and love for making music is put into every accessory we create, and we never stop inspiring performance.