Caliber Gourmet Bullet Thermo Water Bottle 500ml Gold. The Leak Proof lid design allows for the bottle thermos or flask to be able to turn in any direction and unlike a regular portable cup mug carafe or water bottle ours when securely closed is spill and leak proof. Caliber Gourmet Bullet Thermos tumbler is designed to help your coffee tea soda hot chocolate fruit water or other favorite caffeinated or non caffeinated drink last up to 12 hours. This will definitely cover most work days. they chose 17 oz because its bigger than 16 oz portable cups mugs flasks with lids and other smaller funtainer sized bottles while being more portable light weight and easier to carry on the go than 20 oz containers. Specifications for Caliber Gourmet Bullet Thermo Water Bottle: Manufacturer: Caliber Gourmet Color: Gold Fabric/Material: Stainless Steel Volume: 500 ml Hydration Cap Type: Leak-Proof Package Content: Caliber Gourmet Bullet Thermo Water Bottle