My preference is the Stainless Caps with Clear Tube. As I started to juggle 4 Tanks and Juices I quickly realized my system of identifying contents with the Drip Tips was not working. After a disasterous occurence last week mixing juices in one Tank I decided to order more Tanks. When I saw the picture on IBTank's Website with the different colored O-Rings and with guidance from OCD in another thread I placed the Order. I was so stoked to receive the Tanks yesterday and the attached picture is what I affectionately call my Toker. I will now call it my Toker with Racing Stripes. OCD and the Girls hit it out of the Park for me yesterday Thank you so much.