Boveda 62% Humidipak uses 2-way technology ensures relative humidity of 62% (+/- 1%). It establishes ideal humidity within 24- 48 hours, is FDA approved, environmentally friendly (all natural/no harmful chemicals), and can be disposed of without a guilty conscience. Boveda Humidipak lasts approximately 6 months (Humidipak will begin to feel granular inside when it needs replacing). Available in 8g and 67g capacities.