All I vape (chain vape) is 36 mg juice. Most but not all places sell this. I generally order from Tasty Vapor and myfreedomsmokes. Check out the list of vendors and just check their websites to see if they sell it. Generally, the highest nicotine concentration for flavored juice ranges from 24 mg / ml to 48 mg / ml (depending on the vendor). Unflavored juice you can get up to at least 100 mg / ml.