This is a handmade rollerball pen that features Copper plated hardware with a Green acrylic body. This pen is postable, meaning that the cap can be screwed onto the pen body while in use (keeps the cap from rolling away or getting lost while the pen is in use). This pen uses a standard rollerball refill (similar to a Schmidt 888). To replace the ink refill, remove the cap, point the pen body up, and unscrew the tip and remove the old ink refill (keep the pen pointing up as there is a small spring in the pen that you do not want to fall out), replace the ink refill, and screw the tip back on. Note: sometimes the spring will get stuck to the back of the old ink refill - if so, just pull it free and put it back in the pen body.