You just set up your equipment for the first dive of your vacation in Saint somewhere, you start to test the function of your battery operated gear and your computer, camera's flash, film advance or LCD won't function. The worst thing that can happen on a tropical vacation has just happen, No Dive Computer or Camera. Don't leave on a vacation without spare batteries. Why ruin a great holiday because of a few dollars in batteries. You also won't have to pay absorbent island prices, along with not knowing how long the batteries have been sitting in the hot tropical air. Always pack some spares, don't forget your Dive Light needs some too! Batteries make a great Save-A-Dive Kit item.