They can be etched on both sides .eg happy 21st on one side and from such and such on the other,or a saying of your choice.
These are fully customisable . they are approximately 25cm high 15cm long and hold approximately 1.2lites of your favorite beverage.
Also available is a MDF box that has a cut out for displaying the glass after use(it is also able to have writing etched onto it).