Pk/5 Schneider Express Parker-style Ballpoint Refills, Blue Medium Premium quality German manufacturing with wear-resistant stainless steel tip that ensures smooth and consistent delivery until the ink supply is completely used Approximately 10,000 m of writing Waterproof to ISO 12757-10 Fits all Schneider "Plug & Play" ballpoints, and all ballpoint pens using the Parker-style refill Made in Germany