Gold Tip offers the weight systems themselves - they're a standard 8/32" thread and will screw into the back of the inserts.
The PDP weights work also - but they are 6/32" thread, and won't screw directly into the back of the insert, you need an adapter from PDP to go from the 8/32 to 6/32, it weighs 10gr.
Both sets can be found in 5,10, 20, and 50gr increments, the GT set uses a long allen wrench from the nock end of the arrow to screw the weights in and out, PDP uses a similar system.
The GT weights will work on the GT, Vapor, CX, and most .246ID carbons.