Comparison : Item # LV005503B4, LV5503B Series 1/2" Inlet Connection Size and 1/4" Orifice Size Standard Settings Low Pressure Second Stage Regulator
Item # LV005503B6, LV5503B Series 3/4" Inlet Connection Size and 1/4" Orifice Size Standard Settings Low Pressure Second Stage Regulator
Item # LV005503B8, LV5503B Series 3/4" Inlet Connection Size and 9/32" Orifice Size Standard Settings Low Pressure Second Stage Regulator