The Forprime 25 is a small-diameter primer mainly intended for use in tunnelling and other underground applications where bulk explosives are used.

Forprime 25 is a primer typically used in underground charging to ignite bulk emulsions and ANFOs when using a charging unit. The product contains penthrite- and a hexogen-based (PETN and RDX) blue mass. Practically water-insoluble plastic mass has been cartridged into polypropylene tubes. The Forprime 25 tube is light green in colour and, if necessary, it can be fitted with an end plug that also functions as a blasting cap holder.