The Forprime 25 is a small-diameter primer mainly intended for use in tunnel rounds and other underground applications where bulk explosives are used. Forprime 25 is a primary charge typically used in underground charging to ignite bulk emulsions and ANFOs. The product contains penthrite and a hexogen-based (PETN and RDX) blue mass. The practically water-insoluble plastic mass has been cartridged into polypropylene tubes. The Forprime 25 tube is light green and if necessary, it can be fitted with an end plug which also functions as a blasting cap holder.