I ordered these from Banggood using the link Dave L provided.
http://www.banggood.com/4pcs-Countersin ... 29096.html
They took about a week to arrive. 1st impression was that they could have been better packed as all 4 were in a bag together with no protection to stop them knocking into each other. The cutting edges were a little rough as the holes forming them were roughly formed leading to a mildly serrated catting edge. These could be easily dressed with a diamond file but I have tested these as delivered.
I don't have much soft pine around in the workshop but found a bit of 2x1 PAR lurking in the garage with pretty wide spaced growth rings.
I drilled holes to match the shank sizes of 12, 10, 8 and 6mm
and then cut a full depth countersink with each bit at 250 rpm. I always believe in slow countersinking to minimise chatter although this design of cutter is highly unlikely to chatter anyway. This is achieved by most of the cutter body rubbing on the wood so slow speed will avoid burning. So medium pressure only to keep the heat down.
The smallest cutter did pull off centre a bit
the others were much better at centring
These photos were taken with no cleaning up at all and the lack of tear out at maximum diameter ie the part that will be seen is very respectable indeed.
The surface inside the countersink where the bit was cutting across the fibres could have been better but I put this down to not being perfectly sharp but bear in mind this will not be seen.
All in all pretty useful items to have in the workshop and good value for money. Score 9/10
Here they are again in their newly made stand.
Bob