We bought this bike for our children to use during middle school. It is in a rideable but well-loved condition. The wheels are standard 26-inches and the frame is an adult small. I was unable to find the actual model on the Opus site, however, here's a size chart from Opus with the details: https://www.opusbike.com/en/bikes/big-city-en/big-city-op-bigcs-en/