Stolen of the internet. Pretty much the standard grading system.

1 Walking up with crampons. No tools required.
2 A pitch of 60º-70º ice, reasonably consistent, with few short steep steps. Only one tool is needed. Good protection and belays.
3 Sustained 70º-80º ice, usually thick and solid. May contain short, steep sections, but will have good resting places and offer good protection and belays.
4 Sustained 75º-85º ice, separated by good belays, or a less steep pitch with significative vertical sections. Generally good quality ice, offering satisfactory protection.
5 A noticeably more strenuous pitch of good but steep (85º-90º) ice.
6 A very steep, strenuous pitch with few stances for rest. The ice may not be of top quality and protection may be poor. A high level of skill and strength is required.
7 An overhanging, strenuous pitch with few resting places and often poor or no protection.

Too short to even be rated. May qualify as WI2.