These 808D style 1.5 Ohm Dual Coil Tanks are great for an all day vape. Fill them up in the morning and you'll be vaping all day without refilling. The tanks contain a Dual Coil (1.5Ohm resistance) 808D style cartomizer that is surrounded by and acrylic tank, and sealed securely with end caps that have rubber gaskets to ensure no leaking. To fill the tank, simply pull the cartomizer down through the bottom of the tank slightly about 1/2 inch. When done correctly you should see a small gap between the top of the tank and the clear acrylic side of the tank. Tilt the tank slightly and fill directly into the cartomizer until it overflows. Then fill the tank that surrounds the cartomizer completely. After filling push the cartomizer back up inside the tank. Put one of the two included drip tips on the cartomizer and you are ready to vape. When the outside of the tank is dry, refill the tank the same way. PLEASE NOTE: These tanks are threaded for a 808D style e-cigarette. These ARE fully compatible with V4L Diamond Series Manual Batteries, the EGO, and can be used on the 5V OMG with an adapter.