Slot width: 2mm (Phototransistor output)EE-SX1320 EE-SX1321 (2 channels)(Photo IC output)EE-SX4320 / Slot width: 3 mm(Phototransistor output)EE-SX1330 / Slot width: 4 mm(Phototransistor output)EE-SX1340 (Photo IC output)EE-SX3340 EE-SX4340 / Slot width: 5 mm(Phototransistor output)EE-SX1350 (Photo IC output) EE-SX3350 EE-SX4350