To fit on a bicycle using the standard sized spacing for screws on the frame, and hold the standard size bottle. Has some detents at the top to help hold a bottle in place, as well as a lip in front. It also has some holes so water will drain out of it. This is the fourth attempt before I finally got everything to line up right and fit. By the way, while this fits the bottle pictured, it also fits most other bottles, and even does a pretty good job on an ordinary 20oz soda bottle from the grocery store cold case.If you print one, please post an I Made One picture.