Bidirect IEF works with three electrodes. Normally a central cathode and two peripheral anodes. Can also be connected to a central anode when a flatbed professional or a flatbed modular is used. See pictures below. Many samples will run at one time: up to 104! Gel thickness after rehydration is 0.5 mm. On Polyester support. These gels are non-toxic See manual: IEF-cereal