What can I say introduced to this cartridge 1973. Where the record played eventually made its way to Dorset the new home the records played on the Acos still tell the tale on their play back condition. The records are still as black in colour since the day bought with NO frost grave wear. Excellent tracking at very slight stylus pressure. I found a sapphire tip replacement played a softer play back while the more expensive diamond tip slight sharper , but held a longer playing performance. Difficult if any still out there to buy. A Super Mark in The Record World. Paul