With a tip unlike anything we've seen before, the Uni-ball Air is a unique pen, perfect for smooth, expressive writing.

The smartly-designed barrel and translucent grip section taper down to that special tip.

In other rollerballs, the metal ball is held rigidly in a metal surround, with ink only flowing slowly around the edges of the ball.

The Air tip holds the ball in an acetal plastic surround, giving less friction on paper when held at an angle, and allowing the ball to move.

When the ball is pushed up with a little extra pressure, the ink can flow freely around it, giving a thicker, darker, wetter line, similar to a fountain pen.

With light pressure, the ink is only transferred by the ball itself, so you can get finer or broader strokes by varying the pressure a little.

The downsides of all this are that where the ink has flowed fast, it's slower to dry than most rollerballs; and for the thickest lines, you can't scribble very quickly.

These aren't factors likely to be a problem with normal writing, but as with most flexible nibs or even brushes, a little care may be needed when you're getting really inky! The ink in these pens has more dense colour, and spreads less into the paper than similar low-viscosity inks.

As with many of Uni-ball's pens, it's Super Ink, so it's highly permanent and fraud-resistant.

• Sleek tip writes smoothly at any angle
• Features uni Super Ink for 3-way protection against water, fading and fraud
• Elegantly designed with a clean, sophisticated look
• Colour: Red
• Pack of 12