Contractor cleanup bags feature two-ply, low-density construction for uniform sidewall strength. Flat bottoms avoid bottom-seal weak spots and increase capacity 30 percent more than star-bottom bags. Heavy-duty bags include twist ties and come folded in convenient dispenser carton.Contractor cleanup bags feature two-ply, low-density construction for uniform sidewall strength. Flat bottoms avoid bottom-seal weak spots and increase capacity 30 percent more than star-bottom bags. Heavy-duty bags include twist ties and come folded in convenient dispenser carton.