The TE70XP and TE77XP semi-dry transfer units electrotransfer proteins from polyacrylamide gels onto membranes (either nitrocellulose or PVDF) rapidly and efficiently. Their unique design includes an intelligent built-in power supply which automatically monitors the transfer status, stopping the transfer before the stack overheats. The Semi-Dry Transfer Units support as many as two layers of gels being transferred simultaneously. The TE70XP has a 14 x 16 cm maximum transfer area which can handle up to four mini gels using the stacked format. The TE77XP has a 21 x 26 cm transfer area for a capacity of up to 12 mini gels at one time. (1 per EA)