IDEX Super Flangeless™ Short Nut delivers the highest pressure holding for flat bottom fittings that we offer. It effectively eliminates loosening of fittings due to tube twisting and holds tight even during vibration. It has a 1/4-28 Flat-Bottom Port Configuration and is for 1/16 or 1/32 tubing OD. IDEX Nut come in a 10 Pack of natural or as single yellow.