Hydro Air Spa Jet Hydrojet Body Only, 1.5" x 1.5" 10-4100 The original jet with 1-1/2" air&water slip fittings. Air can also be individually vented by a 1/2" port at the top of each jet body. A 2-1/2" mounting hole is required. Hydro Jets are designed to handle 13gpm at 14 psi.