The Pump for 5 Gallon Pail from Rockwell Labs is actually designed to fit a 1 gallon bottle, but Rockwell adds a yellow adapter to the pump that allows it to be threaded on a 5 gallon pour top spout. The products that this is primarily used with has a viscosity of 1000-2000 cP, depending on the flow rate (InVade Bio Drain and InVade Bio Cleaner). The pump can handle products with viscosity up to 3000 cP (centipoise), which is equal to 3 Pa s or 3,000 mPa s. So a very thick resin would not flow through this pump. The manufacturer does not recommend using this pump for heavy solvents.