A medium height V-Stream was mounted on my bike when I bought it. I wasn’t sure that I liked it, so I purchased the larger size. One 20 minute ride was enough to decide that the medium was much better. Since the large screen was still in new condition, V-Stream allowed me to return it for a full refund. I thought that was great customer service. (This took place about five years ago, however, so the return policy may have changed).