Slow, steady release of constant humidity of 70%. Clear polycarbonate cases house crystal gel saturating 450 times their weight with PG solution! Magnet attachment system holds the unit firmly under the lid of your humidor. Watch the crystals...when they shrink to about half their original size, re-charge them with PG Solution. Never let your humidifier go dry again! For the humidification system to work properly, use PG Solution. Other solutions will damage your humidifier.