Here is what they mean folks:
| Code | Type | Notes |
| HB | Bayonet hood | The most common one today. Usually has a flower-petal design. |
| HE | Extension for already existing hood on long lenses | Not very common |
| HK | Slips on the lens, locks with a knob. | Older lenses seems to have this sometimes for long telephoto lenses |
| HN | Screw mount hood | Never seen this one myself. |
| HR | Rubber hood | Great for prime lenses especially if you need to shoot through a glass pane. Keeps the reflexes out so the glass is hardly not visible. |
| HS | Snaps on | Like a lens cap. Never seen this one myself. |
