stand fan:variable speed,motor with long service life and low sound stand fan & stand industrial fan & stand electric fan& industry fan & electric fan1.better impeller structure,low weight and powerful airflow2.Specification of the grill can be required,2 or 3 blade3.suitable for heat-stroke prevention and cooling-down the temperature in miner or factorys4.model:16" ,18" (400mm,500mm) 16",18" ...