Overview Reviews Similar Products Product Description Jandy / Cal Spa U-Joint Knuckles. Used on Cal Spa valves, use 3/4" PVC for rod. Part # PLU21800410 location: LB3-R2B2 Product Videos Product Reviews Find Similar Products by Category Cal Spa Recommended Quick view Cal Spa Auxiliary Panel, SYS4001 $79.95 Add to Cart Quick view Cal Spas Auxiliary Panel, SYS4001BL $79.95 Add to Cart Quick view CAL SPA BLOWER CIRCUIT CONTROLLER $169.95 Add to Cart