*PLUMBERSSTOCK EXPERT* responded:
Hi! Thank you for your interest in our Camco 11582 3/4" aluminum anode rod for American heaters. According to Camco, the size of its top bolt is 1 1/4 inches. For more details, you may want to check page 16 of this Catalog . If this is what you're looking for, just click "Add to Cart" and put your postal code and you're ready to go. If you have other inquiries, feel free to contact one of our customer support specialists at 435-868-4020 or through e-mail @ firstname.lastname@example.org. Have a wonderful day!