Featuring the Mitsubishi Jetstream M17 Refill in your choice of tip size: EF (.5mm) or F (.7mm). This refill is designed for release with the LAMY Safari X Jetstream and contains classic oil-based Black Jetstream ink. The Jetstream M17 Refill is compatible with the M16 refill already found in many LAMY ballpoint pens, and can be used interchangeably.