This kit contains a small package of Humigel crystals sufficient to refill 4-6 times, instructions, a .15 cc scoop to accurately measure the amount of crystals needed and a 10cc. syringe. Including the syringe in this package will both reduce crystals loss and encourage the use of distilled water for filling the humidifier. The dry crystals should retain their potency for 5 years or more. One replacement kit should last for several years even if you have several humidifiers to refill annually.