Dear Mr Parisa,
Thanks for your promptly reply. We suggest our customer to use fiber glass blade, some customer will think stainless steel is more strong, but actually fiber glass is much better. Stainless steel must with rib reinforcement otherwise will no strong enough, but after with the rib reinforcement the windage will be bigger and the electric current increase, also after long time use will case metal fatigue, the curved will become flat then the wind will be less. According to our research, stainless steel blade windage and electric current 10% higher than fiber glass one. Our fiber glass blade already use for 8 years without any complain, it is anti-aging, high intensity, never change the shape. we are very confident and proud of it, so we give customer fiber glass blade lifetime warranty.
Best regards