The 300 Mini Pump Set meters West System 105 resin and 200-series hardeners one full stroke to one full stroke, at both the 5:1 (205/206) and 3:1 (207) ratios. Thread them into the cans once and stop measuring epoxy in cups. The set fits group A (quart) and group B (gallon) containers. Before the first real batch, pump a small test shot and let it cure; if it hardens properly, your calibration is good and every batch after is a matter of counting strokes. Wipe the resin pump nozzle after sessions in a dusty shop, and leave the pumps installed between jobs; they keep the cans sealed. Metered dispensing is most of the reason West System mixes fail less than hand-measured epoxy. If you run 105 in any volume, the pumps pay for themselves on the first bad batch they prevent.
