Moisture can destroy the finest cameras in the world. Not water mind you, but just the dampness of the diving environment. You can't see it, but it's there, and it can cause damage to your equipment unknowingly at an extremely high cost to you. Fantasea's Silica Gel Packs (5 pieces) are the key to preventative maintenance of your underwater photographic equipment. Place then in your housing, your camera, lens, and strobe bags, anywhere you stow electronics. Silica Gel Packs absorb the excess moisture in an environment and keep your sensitive equipment corrosion free when in use or when stowed. Silica Gel Packs are a great Save-A-Dive Kit item. Always carry some spares so you will always have fresh dry absorbent Silica packs on hand. The Silica Gel Pack are measure 2.36" x .8" x .2" (60mm x 20mm x 5mm) and weigh 1.77oz (50g).