I have one of these I found at a garage sale. I will not tell you how much I had to pay for it. Earlier this year, I was told it could be worth as much as $1000. I have seen two on Craigslist...One for $750 and the other for $1500. I won't part with mine.
The name I found was: WWII Nazi German SA NSKK Carl Eickhorn Dagger.
They've have to be in really good condition (near mint) for the $750+ as you can find ones in good condition for $450-550 without much trouble. These are marked the same as yours. There are some marked differently that are closer to the $750 (on the higher side) and then the SS go up a bit more. I've seen some very nice ones in person that were around 2k and there is one that is suppose to be unissued on Gunbroker for $5695 as a starting bid, I'd be surprised if it sells.