Stacked average spectra for faint star-forming galaxies in merging clusters, binned by rest-frame Hα EWs. The 68% confidence intervals are plotted. We only show sources with i-band magnitudes >20 and Hα luminosities between 10⁴⁰ and 10⁴² erg s⁻¹. The average [N II]/Hα ratio decreases with increasing Hα EW. From the low [N II]/Hα ratios, we can infer that the unique population of faint galaxies with high EW (sSFRs) in merging clusters have very low metallicities.