Garrett Vent | Blow-Off Valves recirculating housing outlet hose adapter. Threads into the lower housing on GVB-50R valves to allow the blown off air to be plumbed back into the intake with a hose. Adapters are offered in four diameters: 1.00in/25.4mm | 1.14in/29mm | 1.34in/34mm | 1.50in/38.1mm.