SM321,16DI,DC24V, 0.05MS INPUT DELAY. For Use With: SIMATIC S7-300 Series. Input Type: Digital. Voltage Category: 24 V dc. Length: 125mm. Width: 40mm. Depth: 120mm. Dimensions: 125 x 40 x 120 mm. MPN: 6ES7321-1BH10-0AA0, Siemens