Distribution of the total mass of 5σ_δ peak and their corresponding 2.5σ_δ envelopes (cross points). The x-axis is divided into bins of unit width. For each bin, the median y-value is shown by filled purple circle. The error bars on these points correspond to the Normalized Median Absolute Deviation (NMAD) of the points in that bin. The plot shows that most of massive M_5σδ > 12.8 reside in protoclusters with M_2.5σδ > 10¹⁴ M_⊙.