Smoke Pencil 3oz Refill Fluid Smoke Fluid Refill is the only fluid that works with the Smoke Pencil units. 3oz of smoke fluid lasts 12-15 hours of heavy use in a Smoke Pencil Pro. 3oz size is allowable by TSA for aircraft travel and according to OSHA (1910.1200) this product is non-hazardous. Bottle comes with a nozzle with cap that makes it easy to fill your Smoke Pencil. Specific mixture of water, Glycol and Glycerin is non-toxic.