The rugged construction means it is resilient and will not break under stress. This long life pen will easily outlive a writing endurance of over 10 kilometres (6.2 miles) of ink and the refill installation system has been designed to make it easy to replace the cartridge. For use in wet and greasy work areas it has a matt, slightly textured finish which is none-the-less easy to clean. The natural grip area has a shaped indentation that has been formed with ridges. This not only reduces the possibility of the pen slipping back through the fingers but it also reduces any tendency for it to rotate, especially when the hands are wet.