Hydro Quip 4.0kW Tri Bend Low Flow Heater [D 1] [2.1 3] (26 C3548 1 7T F) defilters Raypak 151 153 155A Tube Bundle is Raypak 151 153 155A Tube Bundle is a replacement heater component for compatible Raypak pool and spa heating systems The dual jets layout gives this panel its practical value because it preserves the control logic of systems with two jet functions while still keeping other common features close at hand Useful when the original heater uses a tri bend low flow format This version is especially useful when the original setup depends on the D 1 style tri bend configuration and the supported 115 or 230 volt compatibility