Brigham Crystal Humidor Unit.

HMD - BRIGHAM CRYSTAL   HUMIDIFICATION (EN/FR) These units contain special gel crystals which absorb 450 times their weight in fluid.  You can actually watch them expand to absorb enough humidor solution for months of freshness. You’ll know when it’s time to refill when the Crystals shrink to half their size.  Can be filled with Distilled water or Brigham Humidor Solution. Available in size 50 - 100 - 250