300 Mini Pumps are designed for convenient and accurate metering of Group A, B, and C WEST SYSTEM 105 Resin-based epoxy. The 300 Mini Pump Set Contains one resin pump and two hardener pumps. Pumps mount directly on the resin and hardener containers and eliminate the mess involved with measuring by weight or volume. 300 Mini Pumps are calibrated to deliver the proper working ratio with one full pump stroke of resin for each one full pump stroke of hardener. 105/205-206 pumps deliver approximate 0.8 fl oz of resin/hardener with one full stroke of each pump. 105/207-209 pumps deliver approximately 0.9 fl oz of resin/hardener with one full stroke of each pump.