GBU648E*S GBU648E*S (GBU648E-S) Base Rack for S2T/S2, 8 Slots (Up to 5 station bus slots). $640.00 | GBU664**S GBU664**S (GBU664--S) Base Rack for S2E, 3 I/O Slots/ Expansion Rack for S2T/S2, $300.00 | EX10-MAI32 EX10-MAI32 Analog Input card 4 Channel, +/-10 Vdc 12 Bit AI32 $509.00 |