Madvapes also has 5v 510 passthroughs. I love mine so far. I'm getting better throat hits, flavor, and vapor from these passthroughs than from my two eGos (1000mah), which I've been disappointed with lately (when comparing the eGos to the passthroughs, that is). The eGos haven't been good for constant vaping. It seems when they are used for a few drags, they need to sit for awhile to cool down before they'll work like they should again.