Accustream replacement mixing tube (nozzle) for Flow® .281 ROCTEC 500 nozzle with performance locating rings. Not interchangable with DiaLine. Nozzle sizes range from .030"-.050". Nozzle length sizes of either 3" or 4". Note: When choosing size and length, if the SKU shows any "X" in the part number that size and length combination isn't offered.