Fillable Caulking Tubes are designed for use with a standard caulking gun. Great for injecting large amounts of WEST SYSTEM Epoxy, laying a lengthy bead of epoxy, making fillets or injecting epoxy into holes as in hardware bonding or repairing cracks in concrete. Can be refilled several times before epoxy begins to cure. Tubes can be refilled again after cured epoxy is popped out.