JT's MEGA-STEAM Smoke Fluid. Thick, dense smoke output yet it dissipates quickly, leaving little or no "train room fog" hanging in the air. Comes in 2oz bottles with "pin-point" end glass droppers for accurate filling. All of our smoke fluids are scented just right, not too heavy, not too light*. Petroleum-based formula. Smoke itself is non-toxic. Keep away from small children. Works with all smoke units.