Slippery slope. I think they are describing the pickup as being hot and having rails. If it was a guitar pickup it would look like more direct intent to infringe in the copyright. It is a decryption not a product name "the two hot rails response ".
It says “NO CLAIM IS MADE TO THE EXCLUSIVE RIGHT TO USE "RAILS" APART FROM THE MARK AS SHOWN” so you can refer to that kind of pickup as a “rails” pickup freely but “hot rails” would be infringing.