PUR HOT MELT from FastbindUSA comes in a 1kg/2.2 lb sealed bag and is in a granulated form. Positive venation should be used with all PUR based hot melt glues and is required for all Fastbind binding applications where PUR glues are used. Because of the nature of PUR hot melt glue, Immediate vacuum sealing and storage in a dry cool area is the only way to extend the useful life of the PUR glue once the packaged has been opened and exposed to humidity. The chemical process that makes PUR so good for book binding starts immediately upon exposure to humidity so usage of the opened packages and immediate vacuum sealing of the unused portion is recommend. Once a package has been opened, the user takes all responsibility of usage and storage of the glue and it can not be returned to FastbindUSA. For more information, contact us here at firstname.lastname@example.org. For the Material Data Safety Sheet and/or the Technical Specification sheet, you can contact us anytime..