【Product parameter】
"Specific size" / manual measurement / a little error
28*20.5 10 inches
30.5*23 11.6 inch
31*24 12 inch/12.1 inch
33*26 13 inch/13.3 inch
36*27 14 inch / 14.1 inch / 14.4 inch
38.5*28 15.6 inch
"Fabric": Water repellent fabric 17 inches is 44*32