These are fantastic vape carts (510 threaded) for filling with medicinal oils. Well made, last for about 5-8 refills, and I have been very happy with them. The whole core of the cartridge heats up as opposed to most others where just the bit around the base of the cart heats up. Very smooth draws. Was getting ready to order some and was happy to find they are doing their winter sale. 75% off typical $7.95 price.