Product Selection Guide CURTAIN WALLS - PRODUCT COMPARISON YKK AP PRODUCT YUW 750 XT High performance, unitized curtain wall system. EFCO KAWNEER OLD CASTLE BUILDING ENVELOPE US ALUMINUM X-Therm® 8750XD 2500 UT Unitwall™ Signature Series Unit Wall - - 2500 PG Wall™ - - YUW 750 XTH High performance, impact resistant, unitized curtain wall system. Page-24 PS-1000-08 | Effective Date: April 28, 2020