... .5", 4", 6" 2)Connection size: 1/8" 1/4" 1/2" 3)CE Certificate Steel Case Gauge 4Z2are high quality dry gauges design ... ,compressors, pool filters as well as commercial and industrial equipments.CASE SIZES:1.5", 2", 2.5", 3.5", 4", 4.5 ... ,compressors, pool filters as well as commercial and industrial equipments.CASE SIZES:1.5", 2", 2.5", 3.5", 4", 4.5 ...