The VB1003 is a 1:1 mix and comes with a plunger for use without an epoxy gun, or you can use it with the gun and the 1:1 plunger that comes with the gun. The VB1001 and VB1002 are 2:1 and you must use the gun with the 2:1 plunger to dispense the epoxy correctly.
Britt