Vapers usually need to replace coils for their vaping devices to pursue better vaping experience. Coils connect the battery and the atomizer that burns the ejuice for you to vape. Voopoo offers various styles of vape coils that give each vaper a unique vaping experience. And Voopoo vape coils are specially designed for UFORCE tanks. So they are called UFORCE coils. The VOOPOO UFORCE Coils presents a bottom vertical structure with ample ports to ensure maximum flavor performance and consistency during extended use. UFORCE coils are divided into five series including U, N, P, R, and D series. Altogether there are 10 kinds of vape coils. UFORCE Coils U Series (UFORCE U2, U4, U6 and U8): Hey, do you know why they are called U2, U4, U6 and U8? UFORCE Coils N Series (UFORCE N1, N2 and N3): UFORCE P, R and D Series: After reading all the above information, do you get the answer now? If you still have some questions about how to choose replacement coils for your voopoo vape mods, please leave a comment below.