Key Features Specially formulated for the BiOrb Air Essential remineralised water to help develop a balanced humidity level in a terrarium Allows terrariums to flourish with clean and healthy water Has reduced minerals and electrolytes to prevent damage to plants 4 x 500ml bottles - 3 bottles with cap lids and one with a spray top Oase BiOrb HumidiMist is a specially forumulated remineralised water with low conductivity and reduced minerals. This combination makes it perfect for use in tropical based terrariums that need a balanced combination of lighting, moisture, air circulation and humidity in order for the plants to thrive. The HumidiMist has been developed to have a mimimal amount of electrolytes to prevent damage to the terrarium or the plants inside. Simply place the liquid into the BiOrbAirs mister unit as required.