The Render K is a compact, machined pen that allows for the use of most rollerball style refills and Parker ballpoint style refills (a black Pilot G2 ink cartridge is included with the pen). These new swappable grip sections are available in several different materials to allow you to customize the look and feel of your pen. The thread-on cap uses triple-start threads to securely attach itself to the pen and to allow the removal of the cap with only 1.5 revolutions. The aluminum version of the Render K has either a tumbled or anodized finish to help protect the aluminum body from damage. The brass and copper versions of the Render K come in a raw finish and will develop a beautiful aged finish with time and use. You can maintain the polished finish on the brass and copper with a jeweler's cloth if you like the bright, shiny finish. Each pen is a little over 5" long and 1/2" in diameter (minus the clip). The aluminum pen weighs 1.1 oz while the brass and copper versions weigh in at a hefty 3.3 oz. We are using the same bulletproof stainless steel clip and screws as we do on our other pens so you don't have to worry about breaking your clip like you do with most pens. Designed and manufactured in the USA.