Comparison : Item # 8500K-40, 4 1/16" Water & Hydraulic Union - American Unit
Item # 8500T-40, 4 1/2" Water & Hydraulic Union - American Unit
Item # 8500K-42, 4 1/16" Water & Hydraulic Union - American Unit
Item # 8500T-42, 4 1/2" Water & Hydraulic Union - American Unit
Item # 8500K-04, 4 1/16" Water & Hydraulic Union - American Unit