So since you're using carto
tanks, I guess you need something modern with a tight draw.
Problem with buying any cartos you might find, once those are done you'll be back here looking for a new tank again. Best to just nip it in the bud and start your transition to a modern tank now.
I would suggest the
innokin zlide tank, 22mm/2ml version, not the 25mm/4ml version. The 25mm/4ml version will work on the K4 but there will be overhang since the K4 mod is only 22mm but it does hold 2ml more
juice, so that's your decision. Some people hate overhang.
Because shipping of vape gear is a shyteshow in the USA due to PACT Act, order it from China and wait 2-8 weeks for delivery. Just be patient You likely wait that long if you order it from the USA anyhow, plus you may have to sign for the package and you will pay more after shipping and taxes.
Here's a link to the 22mm/2ml Zlide in SS color. Use the dropdown menu on the right above the "add to cart" button to select other colors and/or sizes.
EDITED TO ADD: But I'll be frank with you, using a 70PG juice in many modern tanks might prove to be too thin. If you find that you can't use a modern tank without flooding and/or leaking using 70PG, you may have to make your juice a little thicker, like 50PG.
