Home / Appliance / Parts / Captive Air Tank Bladder U20-13 Captive Air Tank Bladder U20-13Price Not Available Price may not be up-to-date. Out of Stock View Product Part Number: U20-13 Brand: STA-RITE INDUSTRIES Seller: Sears PartsDirect Categories: Appliance, Parts Possible Matches$179.99Litheli Cordless Lawn Mower 13 Inch, 5 Heights Adjustment, U20 Seri... Description This bladder (part number U20-13) is for captive air tanks. Bladder U20-13 keeps the air and the water separated in the tank. Follow the instructions in the manual when installing this part.