This Stainless Steel Super Flangeless FlushNut eliminates loosening of fittings due to tube twisting, hold tight even during vibration and delivers the highest pressure holding for flat bottom fittings that we offer. FlushNuts offers the answer for those tight-space applications where nut heads often interfere with each other. It has a 1/4-28 Flat-Bottom port configuration and is for 1/16 and 1/32 OD tubing. It comes as single and in a 10 pack.