  We use extensive model grids to estimate the global parameters of four
partially-eclipsing W UMa contact binaries near the period cutoff. All four
systems consist of K-type main sequence primaries and M-type secondaries that
appear undersized and underluminous for their masses because of the energy
transfer through the common envelope. Three of the four stars exhibit light
curve asymmetry that is explained in terms of magnetic activity and modeled
with dark spots. We discuss the reliability of the photometric mass ratios and
derived absolute parameters in context of total or partial eclipses and compare
them with a sample of totally-eclipsing short-period W UMa systems from the
literature.
