As you can see, our silicone sock has a very good edge treatment,the outer wall is very straight and the edges are perfect Only Compatible with FDM 3D printer equipped with sprite extruder or sprite extruder pro kit, like Ender 3 S1, Ender3 S1 Pro, CR10 Smart Pro, Sermoon V1 and Sermoon V1 Pro 3D Printer heater block Made from high temperature Silicone material , can work for longtime at 300C degree. But PLEASE NOTE if your printing temperature is over 300C degree, please remove the silicone cover before starting printing. High Precise size, It can be assembled more perfectly and is very beautiful. Package: 3pieces silicone covers ONLY Compatible with FDM 3D printer equipped with sprite extruder or sprite extruder pro kit, like Ender 3 S1, Ender3 S1 Pro, CR10 Smart Pro, Sermoon V1 and Sermoon V1 Pro 3D Printer heater block.