I wanted something that I could use to store my gym routine in as I travel to and from the gym. This provides a writing surface and a place to store a pen I can use as I work my way through the gym to make notes on exactly what I accomplished that day. The fact that I can store my plan inside means that the ink won't run due to rain, wet hands or accidental spills. I'm sure that if I dropped it in water it would leak but I can live with that. It seems reasonably durable and is rigid enough for my needs.