Male Luer fittings are used to connect probes and filters on multi-gas instruments. The barbed end fits 1/8 inch Tygon tubing. To ensure you are ordering the correct fitting, please make careful note of the photo above, as the male and female fittings are similar and can cause confusion. Note that on the male fitting, the attachment threads are on the inside and it features a knurled nut for tightening. Packed and sold in a bag of 20.