Ham-Let Stainless Steel 316 Let-Lok Compression Fitting, Nut, 1/4" Tube OD Nut for connecting to a compression tube fitting Connects to a tube or tube fitting Stainless steel 316 for higher strength and greater corrosion resistance than stainless steel 304 Maximum operating temperature range of -100 to +1,000 degrees F Meets ASTM A213 and A269 standards for quality assurance