It Is Made Of PC And Metal, And The Internal Conductor Is Pure Copper. It Is Durable And Can Be Used By You To Adjust The Output Voltage Between 50v-220v. Ultra-Low Voltage DC Motor Regulator With Speed Control Function. This Product Is Suitable For Self-Resetting Fuses. The Current Is Too Large And Will Automatically Disconnect. The Fuse Will Automatically Recover After Cooling. Pwm DC Motor Regulator Specifications: Maximum Output Power: 2000W Using The Latest Bidirectional High-Power Thyristor, The Current Is Adjusted To 25A, Which Is Very Convenient And Solves The Problem Of Overcurrent Caused By Too Small Resistance When The Electric Furnace Wire Is Cooled. The Product Is Accurate And Reliable, And Has Good Long-Term Stability. With Fixing Screw Holes, It Is Convenient To Install And Fix. Small Size, Low Power Consumption, And Fast Response. The Motor Controller Is Connected In Series To The Circuit Of Lights Or Other Electrical Appliances, And Then Turn The Knob To Adjust The Light, Spee Instructions: Connect This Product In Series In The Circuit Of Desk Lamp Or Electrical Appliances, (I.E. Disconnect Any One Of Live Wire Or Neutral Wire Of Desk Lamp, Electrical Appliances, Etc., And Connect The Two Wires Of This "Product") Rotate The Potentiometer The Rotary Rod Can Play The Role Of Light And Shade Adjustment, Speed Regulation, Pressure Regulation And Temperature Regulation; It Is Very Convenient To Use. This Product Is Suitable For: Using A Type Of Bidirectional High-Power Thyristor, Because The Current Can Reach 25 Amps, Which Solves The Problem Of Overcurrent Caused By Too Small Resistance Of The Electric Furnace Wire When It Is Cooling; It Can Easily Adjust The Mains Power The Output Voltage Can Be Adjusted Arbitrarily Between 90----220 Volts For Use By Electrical Appliances. Such As: Electric Furnace, Water Heater He