Solar Cell: Mono 125mm*31mm Maximum Power 20W Optimum Power Voltage(Vmp) 18.36V Optimum Operating Current(lmp) 1.2A Open Circuit Voltage (Voc) 21.9V Short Circuit Current(lsc) 1.3A Number of Cell 36 cells Size of Module 632mm*304mm*30mm Net Weight per Piece 2.5KG Cell Efficiency (%) 15% Solar module Efficiency for 20W(%) 10.5% Watt tolerance(%) 5% . Carton.