I was selling these heads "as is" straight from the machine but then had a few issues with people saying they are worn etc etc
So now I am doing the following
I send the heads away to be professionally relapped and tested
Heads are sent to the relap shop and examined they (not me) determine if the heads are good enough for sale,
They are Initially inspected , if they are deemed to be too far gone they will be rejected and thrown away.
Then they have to be electrically checked for inductance, again if any problems they are binned.
Then they get relapped back to the correct specification, this is not an easy job as often on the heads there is an uneven wear pattern so this has to be corrected.
After the heads are re examined microscopically if no good they will be rejected, if ok they will be retested and a test report of the Inductances both before and after is created.
They are then sent back to me, all of this costs a lot of money and time.
I see people selling these heads on ebay for 60-90£ , sold as is with no guarantees etc and if you are lucky enough to get a good one you will still have to have it relapped and thats 30-40£ plus postage and you need to wait ,so these represent good value, and funny enough they perform better than the originals.
Heads were the most expensive item on a Reel to reel recorder , Tascam Ninjas renovated heads offer good value for money, and are guaranteed to perform as good as or better than the new heads.