The Tombow AirPress Ballpoint Pen was built for someone with an extremely active lifestyle. It allows the user to write in a variety of unusual situations. With the Tombow AirPress Ballpoint Pen you’ll be able to write upside down, anywhere, anytime. Buy It Here: $9.37
There is a built-in pressure chamber inside of the pen, and it can be activated by just one click of the button. This is the feature which enables the user to write upside down. There is also a sturdy rubberized coating around the pen which allows the writer to hold the pen in wet conditions, or while wearing gloves.
The Tombow AirPress Ballpoint Pen was built with an active user in mind, for someone with a lifestyle that puts them into a lot of precarious situations. They’ve almost certainly achieved their goal of designing the ultimate active pen, and somehow managed to keep the price point below $10.