Schmidt 5888 - Black Ink - Metal Body Safety Ceramic Rollerball Refill, stainless steel tip with 0.6 mm ceramic ball, Fine Tip. 

• Fits “ ystudio - Classic/ Brassing/ Resin Rollerball Pen”
• Fits 98% of all Rollerball pens that accept a standard size refill.
• Refill Reads: SCHMIDT Safety ceramic roller 5888 F non-dry refill.
• Length: approx. 110 mm
• Diameter: 6.3 mm
• Made in Germany