GustBuster Metro Automatic Sunblok Umbrella (Silver, 43-Inch) by GustBuster. $35.28. GustBuster Metro Automatic SunBlok will not only withstand winds of 55+ mph but will also will also protect you from harmful UVA and UVB sunrays. Same features as the standard GustBuster Metro but will also cut the temperature by up to 10 degrees. Patented technology allows wind to pass thru the teardrop shaped vent holes. Comes with a limited lifetime warranty.