Part Number AT1-B2-11-640-521-MK Circuit Breaker Accessories in stock with ready to ship. Get an instant quote for Carling Technologies Inc part number AT1-B2-11-640-521-MK by filling form below with your desired order quantity, targeted price and the expected order-fulfilment date. Get instant quote for AT1-B2-11-640-521-MK. Our dedicated account manager will get back to you within 15 minutes.