Attention: Not all German plugs fit.

The plugs fit in the local outlets - whether with or without grounding - also good pure.

What a frustration, as the German power plug my laptop (with ground) did not fit in the German part of the adapter.
Plastic nipple prevent active that you use the adapter with circular connector with protective contacts. This is probably due to the security. Only when one takes a trip around the world, you have to compromise on this aspect anyway. Especially in emerging markets with functioning electrical outlets ground are not always, or even more rarely seen.

A file with which I was able to cut the plastic nipples to a suitable length, I unfortunately did not have on hand.

From the product description:
"Ensures a secure connection to your double insulated appliances with protection class II (without earthing contact)"
I had unfortunately ignored.

So be careful! The product is far from universal usable, but only for flat plugs without earthing contacts!