The male of the flareless tube fitting has a 24° seat and a straight thread. The female half has a compression sleeve and a straight thread. In addition to the sleeve, a female nut and a tube form part of the female connection. On the male, the seal takes place between the 24° seat and the compression sleeve. On the female, the seal takes place between the tubing and the compression sleeve. The threads engage to form a mechanically strong connection.