Compatible Models: The black silicone heat block cover is compatible with Prusa MK4 and Prusa XL 3D printers. Perfect DIY 3D printer parts for all high-precision metal nozzles. Design: The silicone cover keeps the heat block clean, preventing plastic from burning, blackening, and accumulating, which extends the lifespan of the heat block and extruder; maintains a stable hotend temperature and prevents failures in 3D printing projects. Easy to Install: With good flexibility, it can be placed close to the heat block, making it easy to install, stable, and not easy to disassemble; very robust. SILICONE MATERIAL: Made of heat-resistant, injection-molded, non-stick silicone, capable of withstanding temperatures up to 280°C/536°F. Helps keep the hotend clean and stable. High Temperature Resistance: You can safely print more exotic materials, such as PETG, at higher temperatures while using the cooling fan at full speed. Actively keeping the hotend very hot and cooling PETG faster before it is placed on the heated bed can help increase the success rate of more prints. 16.5*15*24mm.