Reusable aluminum water bottles are better for the environment than purchasing bottled water or other drinks in plastic containers, but if you have one, you may have noticed how well aluminum conducts heat. With a bit of insulation, you can keep your beverage and your fingers at their own temperatures longer. This is a small project, so you could easily complete it using remnants of yarn from other projects.This article gives information on making the cozy to a custom size alongside numbers of stitches used to obtain the specific result pictured. Use whichever seems to work best for you. Working through parts about the custom size will teach you a lot about crocheting without a pattern; in fact, you could crochet any cylindrical object with confidence this way. The materials shown are listed under Things You'll Need below.