These socks will keep your nozzle clean and free of burnt on blackened plastic. They don’t just keep the nozzle clean, but also keep heat inside the hotend, and off the print.
Made of a heat-resistant, non-stick silicone material that will repel build-up of molten plastic. This really helps with sticky materials like Co-Polyesters and filled materials that like to build up on nozzles.
These also offer a huge boost in temperature stability, particularly if you use high airflow cooling around the nozzle to cool the print. The additional cooling combined with reduced radiation of heat from the block and nozzle to the print really boost the ability to print great overhangs and bridges, all while keeping the hotend temperature extremely stable.
Socks don't last forever. Depending on what materials you print and how much abuse they get they eventually wear away at the nozzle tip. Even with sticky abrasive materials and a bit of abuse they should easily last 100+ print hours. With less sticky materials like ABS and gentler use you can get almost infinite life