System H shows a strong emission line at 4851 Å which we interpret as Lyman-α at z = 2.99 from the lensing configuration and the lack of additional emission lines. The dotted line is the sky noise spectrum (no sky emission line are present in this wavelength range). The other likely alternative is [OII], observed at 4851 Å would give a redshift of 0.301, similar to the cluster redshift, thus the alternative can be excluded.