A classic in the eraser world: the Staedtler Mini Rasoplast eraser! 

I've used these erasers since school - the quality is excellent and they last an exceptionally long time when cared for well.

This eraser is medium-firm hardness and is perfect for correcting HB-4B graphite.

Each Staedtler Mini Rasoplast Eraser measures 3 x 1.5 x 1cm in size. This listing is for one Eraser.