These socks keep your nozzle clean and will not burn on blackened plastic. Not only do they keep the nozzle clean, but they also keep the heat in the HotEnd and away from the print.
Made of a heat resistant, non-stick silicone material that repels the build up of melted plastic. This really helps with sticky materials like co-polyesters and filled materials that like to build up on nozzles.
These also provide a huge increase in temperature stability, especially if you use high airflow cooling around the nozzle to cool the print. The additional cooling combined with the reduced heat radiation from the block and nozzle to the print increases the ability to print large overhangs and bridges while keeping the HotEnd temperature extremely stable.
The covers simply slide onto the front of the HotEnd without disassembly - they fit tightly when first slid on when cold. When hot, the silicone expands to the correct size to fit the HotEnd. The elastic material fits all nozzle sizes in the range from 0.25 mm to 0.80 mm