The Bog Fog Extreme High Density HDF mix from Froggy's Fog generates an extremely high density, white, airborne fog with a very high index of refraction and slower evaporation rate. It is well suited for scenic obscuring and strobes "white-out". It is a very high density fog and is the perfect choice for complete loss of visual reference. The only choice for "fog-out" or "white-out" conditions. Bog Fog is part of the Designer Select Series of Theatrical Effects Fluids from Froggy's Fog. All Designer Select (DS) Water Based Fluids are made from lab-grade UV-Filtered de-ionized water and pharmaceutical grade chemicals. DS Fluids contain no glycerol/glycerin and all Designer Select Fluids adhere to the strict specific gravity and density requirements of major fog and haze machine manufactures. Froggy's Fog uses the best chemicals so you get the best results from your machine. You can rest assured that each of the fluids in the Designers Select line from Froggy's Fog has been designed with the longevity of your fog and haze machine in mind.