INSERT FOR BRASS NUT/ for use with Nut part#261P06. 260P-06NYLO-Seal Insert Sleeve | For 3/8-inch TubingNYLO-Seal Nylon tube fittings have excellent resistance to acids, oils and greases. Installation time is reduced with NYLO-Seal fittings when compared to regular compression or flare fittings. Wh..