It's crucial to power off the printer before performing any maintenance work on the printer and its electronics, including tool head wires, because leaving the printer on while conducting such tasks can cause a short circuit, which can lead to additional electronic damage and safety hazards. When you perform maintenance or troubleshooting on the printer, you may be required to disassemble some parts, including the hotend. This process can expose wires and electrical components that could potentially short circuit if they come into contact with each other or with other metal or electronic components while the printer is still on. This can damage the electronics of the printer and cause further damage. Therefore, it's essential to switch off the printer and disconnect it from the power source before doing any maintenance work. This prevent any short circuits or damage to the printer's electronics. By doing so, you can avoid potential damage to the printer's electronic components and that the maintenance work is performed safely and effectively. Please note:the physical slightly color difference or difference, does not affect the use, please do not mind, thank you! Color:As Shown Material:Metal Package Contents: 3 * Extrusion Head Cutter Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.