  We present theoretical X-ray line profiles from a range of model colliding
wind systems. In particular, we investigate the effects of varying the stellar
mass-loss rates, the wind speeds, and the viewing orientation. We find that a
wide range of theoretical line profile shapes is possible, varying with orbital
inclination and phase. At or near conjunction, the lines have approximately
Gaussian profiles, with small widths (HWHM ~ 0.1 v_\infty) and definite blue-
or redshifts (depending on whether the star with the weaker wind is in front or
behind). When the system is viewed at quadrature, the lines are generally much
broader (HWHM ~ v_\infty), flat-topped and unshifted. Local absorption can have
a major effect on the observed profiles - in systems with mass-loss rates of a
few times 10^{-6} Msol/yr the lower energy lines (E <~ 1 kev) are particularly
affected. This generally results in blueward-skewed profiles, especially when
the system is viewed through the dense wind of the primary. The orbital
variation of the line widths and shifts is reduced in a low inclination binary.
The extreme case is a binary with i = 0 degrees, for which we would expect no
line profile variation.
