Square D 8501XTE1Product Attribute Attribute Value For Use With All 8501XDO XO Relays Function On Delay Mounting Type Relay Mounted Series 8501 Series Type Pneumatic UPC Code 785901537342 Overview Class 8501 Type X Relays combine a rugged, heavy duty design with modular construction for greater flexibility. They are ideal for those applications where long life, high reliability and ease of maintenance are important. They Type X family offers a complete line of relays