With the WaterWriter you can easily write in wet, greasy or sandy conditions. The pen is under pressure so works on every corner, writes on all the waterproof paper (and all other paper types), without stains and has a specially shaped exterior for grip. No spring mechanism in the pin, so grit and dirt can not penetrate. It is really the strongest, most comfortable pen available.
The triangular top minimizes rolling on a tabletop or in boats or aircraft.