S7120-7K SMI Control Module(0) No Reviews yet $227.25 Quantity discounts available QuantityPrice SKU: S7120-7K Quantity -+ Add to Cart Details SMI control module for 7-Series stop & cross arms.Also available as retrofit version for 6-Series p/n S7129 Can be used in 6-Ser... DetailsBackDetailsSMI control module for 7-Series stop & cross arms.Also available as retrofit version for 6-Series p/n S7129 Can be used in 6-Series units but connectors have to be cut off & wires spliced. See larger photos for wiring info. Reviews 0 BackRatings & ReviewsNo reviews availableBe the first to Write a Review