BIC Marking Retractable Permanent Marker conveniently retracts with just one click! It has bold, long-lasting color & a durable fine point tip. Seal Guard Defends Against Dry Out. These markers mark on just about everything: glass, metal, plastic, photos, foils & coated paper as well as oily & damp surfaces. Low-odor, acid-free ink (no added acid; no measurable pH). Marker Ink Type: Permanent; Marker Tip Type: Bullet; Marker Tip Size (text): Fine; Marker Color(s): Black.