The ultimate in Survival Gear, a must have for any outdoorsman, hiker, camper, solider or just a plain old Survivalist. This is a Aluminum waterproof storage capsule with o-ring seal. These are great to have to store and keep dry any of your small items. The capsule is around 3 1/4 inch long with a 1 inch diameter. Capsule also has a 3/4 inch Split ring for easy attachment.