SM321, 32DI, AC120V. For Use With: SIMATIC S7-300 Series. Module Type: Input. Input Type: Digital. Voltage Category: 120 V ac. Length: 125mm. Width: 40mm. Depth: 120mm. Dimensions: 125 x 40 x 120 mm. MPN: 6ES7321-1EL00-0AA0, Siemens