Size: 23x16x11.5mm, there is a 3.1mm ID hole for OD3mm temperature sensor Made from Premium copper material with surface Nickel plating,Rated to 500 °C for even the most demanding tasks,Compatible with all filaments,from basic PLAs to custom high-grade PAEKs Copper material has good thermal conductivity and high strength and high temperature. Compatible with Phaetus Dragon Hotend Standard High Flow Extruder 3D printer Package: 1 piece plated copper heater block