An electroblotting cassette is formed in three separable parts—an upper plate, a lower plate, and a base that receives both plates, with electrodes mounted on both the upper and lower plates. The cassette accommodates transfer stacks of different thicknesses by its inclusion of a set of raised areas, known as “lands,” on the floor of the base and a set of inverse lands on the underside of the lower electrode plate, the two sets being spatially arranged to either abut each other or be offset from each other, depending on the orientation of the lower plate, thereby allowing the user a choice between two heights of the lower plate within the base and hence two thicknesses of transfer stacks. Other arrangements include those with more than one set of lands on one or both parts to allow for three or more thickness selections, or depressions in place of lands. Finger-operated latches secure the upper plate to the base.