If you're unsure about the rollerball refill for your Cross pen, there are two choices. A slim rollerball refill for very thin Cross rollerball pens such as the Century Classic and Spire series. More commonly, the regular Cross rollerball is used, particularly in the regular diameter pens. All Cross rollerball pens have a removable cap when ready to write, with the exception of the Edge and the Matrix.
Cross ballpoints deploy with a twist of the top. The standard refill has a slim metal tube with a threaded plastic top piece. In the Cross brand you have fine, medium and broad point choices, all with standard ballpoint ink. Monteverde has a great option in liquid ink and a rainbow of colors.
Your Cross fountain pen, again, has two options in ink cartridges - slim or regular. If your Cross is very slim (Century Classic, Spire), then the slim cartridges. All others use the standard Cross cartridge. An ink converter and numerous bottled ink options exist as well. Just click on the fountain pen window below.
Cross multi-pens use standard mini ballpoint refills and .5mm lead. Click on the window below to match your exact refill needs from ballpoints, to lead, to erasers.