OK,
i would class these as 510 lights.
they have a rubber end cap for easy refilling.
they are not as good as a std 510 attie in terms of hit or oddly enough flavour.
they take about 20 drops to fill however do require topping off every now and then. Also the taste. They taste dirtyer than a std 510. Sorta burnt.
The answere to the poor build quality issues of the std 510? No
The answer to constantly topping off? No
The answer to leaking carts? Yes
For 99p handy for emergancys, handy for strong liquid flavours and handy for letting people try out e-cigs.
would I
buy another few? Yeah probably