It is more difficult to find SW Sextantis systems with low inclination, since it is necessary to examine many stellar spectra without being able to restrict to eclipsing variables; however, surveys have been performed, and suggest that some of the observed properties of SW Sextantis stars are accidental results of a sample restricted to high inclination systems [1] Emission lines of hydrogen (the Balmer series) and helium are observed, and are not doubled (as one would expect by Doppler shift of light emitted from the edges of a fast-rotating disc), but the wings are broadened to the point that the spread of source velocities can be as much as 4000 km/s.
For a brief period near phase 0.5 of their orbits, SW Sextantis stars do show doubling of their emission lines and this is a defining character of the class.
Models of SW Sextantis stars must explain the high mass transfer rate and the period distribution just above the period-gap.
The standard theory of cataclysmic variables suggests that the rate of mass transfer is determined by loss of angular momentum due to magnetic fields.
[7] Donald W. Hoard at the Max Planck Institute for Astronomy in Heidelberg maintains a list [8] of SW Sextantis stars mentioned in the literature, and a description [9] of the characteristics used to identify them.