20 plastic preforms with 20 plastic caps. Reusable, heavy duty gage PET Plastic. Dimensions: 3-3/4" Long x 1" to 3/4" OD. (95mm Long x 28mm mouth by 25mm to 20mm OD body). Interior liquid capacity = 16ml (.54 fl oz). Reliable container. A stash container. Smell proof, waterproof, weatherproof, impact resistant, freezer and dishwasher safe. Airtight, withstand water submersion, humidity, and dirt. Similar to a test tube with screw cap but stronger. Best geocache container available for geocaching games. A bison tube. NOW WITH NEW AND IMPROVED STRONG CAPS.