These rotors are for rebuilding your oil pump.
Standard rotors are not available anymore, so you have the choice of buying a secondhand pump and hoping the rotors might be ok. most rotors especially on the pressure side are worn out, the problem is the light does not come on until a minimum of 8psi is reached, so most of us will be blissfully unaware that when your engine is hot and the oil is thin, your oil pressure can be really low and you will not know. So engine damage could be occurring especially those camshaft carriers in the head.
These rotors are machined individually, the geometry is slightly different and the running clearance is improved. this is possible because of the different manufacturing process.
We have tested these in the smith Honda, CR1 and the new CRS and we have had really positive results. hence they are now offered for purchase.
These are equally as good in a standard engine as well as a performance engine because they give good pressure at tickover compared to original equipment.
WARNING:- The performance mod used to be to shim the relief valve in the pump body, this is not recommended with the these rotors as oil pressure becomes too high and risks failed seals etc.
see also oil pump rebuild service