Pentel EnerGel Refills 0.7 Black Metal Tip

Pentel Refill Ink for EnerGel Liquid Gel Pen, (0.7mm), Metal Tip, Black Ink, Box of 12 (LR7-A)

Pentel

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These are my preferred refills for the Philography. They also have a needle tip version in 0.7 and various other sizes and colors. I like the metal tip. It feels more sturdy to me.