The design, construction, and use of a simple inexpensive system for multiple slab gel electrophoreses are described. Each gel slab is cooled from both sides by an electrode buffer. The electrophoresis time of each gel can be easily controlled independently from the others in the set. Because this set is very simple, it was completely handmade by the author. Depending on the purpose for which the set is to be used, its size, thickness, and shape can be changed.