Transform your TFV4 Mini into a Micro TFV4! The backup kit includes two shorty-sized cores and the same shorty-sized replacement glass tube. Shorty TFV4 MINI has become more compact and beautiful. Its size has reduced by about 10%, but capacity increased by about 14%, from the default of 3.5 ml to 4 ml. Small core, large capacity, less juice consumption, New TFV4 MINI backup kit can make your vaping experience better!