Comparison : Item # 105-2S, 1/8" O.D. Tube Inverted Flare Fitting - Steel Standard Nut
Item # 105-3S, 3/16" O.D. Tube Inverted Flare Fitting - Steel Standard Nut
Item # 105-4S, 1/4" O.D. Tube Inverted Flare Fitting - Steel Standard Nut
Item # 105-5S, 5/16" O.D. Tube Inverted Flare Fitting - Steel Standard Nut
Item # 105-6S, 3/8" O.D. Tube Inverted Flare Fitting - Steel Standard Nut