Offering a rare dimension of versatility, every RETRAKT comes with two springs that enable you to use both Pilot G2 and Parker-style refills in the same pen. While the aluminum is anodized and will retain its finish, the raw brass and copper versions will develop patinas over time. The aluminum version is fairly lightweight at 1 ounce, while the brass and copper weigh in at a hefty 2.5 ounces each.