Those brown batteries are 3000 mah not 300 and are likely to be LG's if they are not fake. Thing with batteries is to be careful you buy them from a reputable source since there are a lot of fake ones out there. I believe Liion Wholesale is a recommended supplier.
The "dia" they are referring to is the inner diameter of the wire coil itself. The Ijoy looks to be a fairly large RTDA so I'm sure you'd be fine with anything up to a 4 mm diameter, though I'd probably go 3 mm myself with SS316L (stainless steel wire) 24 gauge for 2
coils at a combined 0.25 ohms with (if memory serves) 7 wraps. Use the Coil Calculator web site to determine how to build the coil you want. Remember if you are building a dual coil setup that they both must be identical and their resistance will be halved (ie: 2 - 40 ohm
coils in parallel will result in a .20 ohm build).
I see no point in buying the plain
coils if you are buying a coil maker tool since a roll of wire is a lot cheaper and easier to buy. I bought the 8 variety kit of specialty coils just to see if they were that much better but haven't seen much improvement so just went back to plain DIY coils. The only store bought coil that I've been impressed with is a notched coil.
