m_F160W vs. m_F110W − m_F160W CMD (left) and m_F606W vs. (m_F606W − m_F160W) − 0.35(m_F110W − m_F160W) pseudo-CMD of NGC 288 stars. The probable 1G and 2G M dwarfs, selected from the CMD in the left panel, and the corresponding fiducial lines are colored red and blue, respectively. Dotted lines represent the fiducials of equal-mass binaries (i.e. the MS shifted upward by 0.752 mag). The remaining stars are colored gray, and the fiducial lines of the upper MS are represented by black lines. Typical error bars are shown in red on the left.