While similar in a lot of ways, personalized plastic water bottles and plastic travel tumblers differ somewhat in how and where they are used. Travel tumblers are more like cups with a lid and are generally meant to be kept upright, held in cupholders in your car or hanging out on your desk. While travel tumblers come with lids to help prevent spills, and some can even be flipped in any direction when fully sealed, they are structured like cups and meant to be handled like them.
Plastic water bottles, on the other hand, are made to retain liquid at any angle while on the go. They can be strapped to your bike, left loose in your backpack, or carried in big pockets. The shape of the custom plastic water bottle makes it easy to grip or strap down and typically they are made with spouts that allow you to drink spill-free at any angle. Both, however, help you carry your drink on the go and are a great way to get your custom logo seen.