I just went down to the kitchen and measured my favorite coffee mug. It's 16 ounces. Granted, it's on the big side. I like it when I'm filling it up once and then going out to the garage or back yard. A smaller mug is great if the plan is to stay inside, get a couple refills, and keep it hot. Anywhere from 12-16 ounces is fine. The handle MUST be able to accommodate three man-sized fingers. Anything smaller, and I feel like I should be wearing a bow tie and nibbling on scones. Not that there's anything wrong with bow ties and scones... The other consideration... and I'm sure you have a whole team of experts devoted to this subject... is price. I have enough really cool promotional cups and shirts to last a lifetime. But if another cool cup or shirt shows up at my price point, my clicky-finger can't resist.sal wrote: ↑Mon May 18, 2020 5:23 pmI will probably begin with a 12 oz. mug that is straight sided and the top and bottom are the same size and the handle is large enough and can hang the mug on a hook up or down. I believe this is the most efficient shape. I will see if they make a larger version?