This RTA is very good performs very well.Its one of the best wicking tanks i own.The build quality is perfect i bottom fill mines no leaks.The draw was quite loose so i put 3 orings on the inside off the 510 bottom plate I did not think it would work but improves the draw a lot,tightens the draw and makes it super smooth.I think the o'ring size i used was 14 x 1.5mm