Pentel Orenz 0,5 mm Cherry Red

With Pentel Orenz unique lead protection, you no longer have to worry about the lead coming off. The built-in tube protects the lead all the way to the paper, and its rounded corners prevent the lead cover from getting in the way and scratching the paper as you write. As the lead wears down, the protection follows up to the pen body. When you have finished using the pen, you can push the entire support tube into the pen. 

This model takes 0.5 mm leads.

Eraser refills can be found here.

Also available in other designs.