  Photometric observations in Sloan g' and i' bands of four W UMa stars, NSVS
2244206, NSVS 908513, CSS J004004.7+385531, VSX J062624.4+570907, are
presented. The light curve solutions reveal that all targets have overcontact
configurations with fillout factor within 0.15-0.26. Their components are of
G-K spectral type and almost in thermal contacts. They are relatively close
also in size and luminosity: the radius rations r_2/r_1 are within 0.75-0.90;
the luminosity ratios l_2/l_1 are within 0.53-0.63. The results of the light
curve solution of CSS J004007.7+385531 imply weak limb-darkening effect of its
primary component and possible presence of additional absorbing feature in the
system.
