Comparison : Item # 262R-86, 1/2 x 3/8" O.D. Tube Standard Nut Compression Fitting - Reducing Straight Union - Drilled Thru (Slip Style)
Item # 262R-106, 5/8 x 3/8" O.D. Tube Standard Nut Compression Fitting - Reducing Straight Union - Drilled Thru (Slip Style)