The Small Vessel has the same basic shape and features as the Standard Vesesel, but with a smaller diameter cavity.  Dimensions of the cylindrical cavity are 4.5 inches in diameter by 2.8 inches deep, so that it easily holds 500 ml of cryogenic liquid.
 
Spearlab foam dewars are effective and durable vessels for handling liquid nitrogen and cryogenic materials. They have gained acceptance as the preferred containers for x-ray crystallography samples, and also are used in a wide variety of other cryogenic applications. Unlike conventional glass and stainless steel Dewar flasks which depend upon a vacuum layer for insulation, Spearlab foam dewars use a fine closed cell foam for insulation. This foam material is chemically inert and mechanically durable enough to be exposed directly to liquid nitrogen, without leaking or degrading.