Got my GGTS today (#133) and the red 3000mah 18650 3.7v fit fine, a hair snug, but put in through the top they do great. A great piece of equipment and great looking, there are some weird stains in the maching on the top sleeve but will look under magnification and likely find that I can clean it. This thing puts out unbelieveable vapor @ 6 v with 901 (great taste), 3.7v with 510 great throat. 6 v requires HV atty cause burns liquid quickly. All in all the best vaping that I have experienced so far.