The sleeve with a screw is installed with a kit to turn the base

1. These stainless steel kits can be picked up by magnets.This universal cartridge installation kit contains everything you need to install into any turntable cartridge.This range of screws, nuts and washers accommodates a full range of valve core depth requirements.
2. Please note that this mounting kit is made of high-strength stainless steel, not aluminum, as many cartridge manufacturers specifically recommend against the use of aluminum.For example, the installation instructions for the 2-meter orthofon cartridge clearly state, "Never overtighten and never use aluminum screws as they may get stuck in the threaded holes of the mounting plate." The weight of the stainless steel screws relative to the aluminum or other material also doesn't matter, as you should always adjust the counterweight on the back of the arm to ensure you set the correct vertical tracking force for the cartridge and pen