color matching across a large project doesn't depend on guessing whether a close-enough substitute will read right next to the original reference

Pentel White X100-W is a small marker made out of metal

and a removable Multifoil sheet slides behind the active page to stop ink from bleeding through to the sheets underneath

This pack includes twelve different neutral grey markers and you can add to them by buying different colours separately here: Stylefile Marker Classic

flux empty marker fx pump 150e Molotow ONE4ALL markers and refills color matching across a largeA handy pump valve marker with a easy refill in the bottom and a 15mm broad tip.