This works in my Rocket Giotto, replacing the weird ceramic mushroom head that is pre-installed (which cracked since I had not cleaned/serviced my machine in two years.
The bolt is quite similar to the original, however, it is not as rounded (it's a touch more industrial, but no one will notice the difference).
Make sure to also purchase the proper o-ring, as this does not come with one. This also does not come with the teflon ring either - and I just reused my old one, no problem.
The original filter screen also fits on top of this.