A502/4 & A502/4 Plus Company 3-State, Germany   Date 1991   Amiga A500   Interface trapdoor slot   four ZIP sockets with 2 MB RAM 1M×4 ZIPs (514400) A502/4: 80 ns ZIPs A502/4 Plus: 70 ns ZIPs connects to the trapdoor slot battery backed up clock disable switch