Custom Cones USA Fast Fill 121 Replacement Cartridge, 84mm ConeFast Fill Makes Pre Roll Filling Simple & Easy Wether you're looking to buy extra cartridges to preload your cones, or you're just wanting the ability to pick and choose, Custom Cones has exactly what you need. What makes the Fast Fit 121 great, is that the base units are the same for both the Fast Fit 55 & 21. That means, if you decided to start with the 55, you could easily upgrade by just purchasing 121 cartridges! Or vice versa, say you purchased