For those of you looking for a more affordable replacement for the Voigtländer LH-6 (or even LH-8) bayonet-mount hood for your Nokton 40/1.4 (or 40/1.2) lens, here it is.
Most third party manufacturers produce hoods that screw into the filter, but this is the only third party solution I am aware of that mounts directly on to the lens, just like the OEM Voigtländer.
And it’s half the cost. Highly recommended.
—Peter.
Prosophos 
The haoge hoods are great, I like their metal square ones, really well made at a good price
Yes, I saw the square ones which looked nice too but chose the classic round that’s more like Voigtländer’s design.
Incidentally, these hoods are a little less thick than Voigtländer’s, and consequently lighter (which I prefer). They’re still made of metal though.