The cooling fan is used to cool and reduce the temperature of the hot end ceramic heater. The cooling fan is a high-speed rotating component, please do not touch it during operation. In addition, our hot end cooling fan automatically shut down after being stuck at rated voltage for 1-3 seconds. The circuit attempted to restart within 2-6 seconds. Even if the rotor is locked for more than 72 hours, it not cause damage. The only difference between the is the structure of the terminal connector. With the update of the version structure, the reliability of terminal connectors has been improved under extreme conditions. Due to different batches, there may be differences in product appearance, color, and printed text, which not affect the use. Colour:Black Material:Plastic Type: B: for P1P 2510 Axial Fan Package Contents: 1x Axial-flow fans 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.