Abstract: A marker having a body, a core having an ink and the core being within the body, and a tip having a first end connected to the core and the tip extending from the body towards a second end. The tip further has a first side opposite a second side and a front side opposite a back side, with the first side and second side therebetween. The second end has a concave section between the first side and the second side and the concave section is configured to accommodate a circumferential arc of intravenous tubing within the concave section to deposit the ink.