Uforce U Coils. 5 Pack.
The Freemax coils found HERE are compatible with Uforce tanks.
Replacement coils for the Uforce tank by VooPoo.
N1 0.13 Ohm Mesh coil. (50-100W / best 70-80W)
U2 0.4 Ohm dual coils (40-80W / best 55-65W)
U4 0.23 Ohm quadruple coil (50-120W / best 60-80W)
U6 0.15 Ohm Sextuple coil. (65-110W / best 80-90W)
U8 0.15 Ohm Octuple coil. (70-130W /best 90-110W)
P2 0.6 Ohm (24 - 28 Watts)
N2 0.3 Ohm Dual Mesh (45-80W / Best at 55-65W)
N3 0.2 Ohm Triple Mesh (65-100W / Best at 75-85W)
More information can be found here