When evaluating double mesh fabric, you must prioritize GSM (Grams per Square Meter), which typically ranges from 150 to 400 GSM depending on the application. Ensure the material composition is clearly defined, such as 100% Polyester or Nylon blends with Spandex for elasticity. Additionally, verify the breathability rating and moisture-wicking capabilities, especially for athletic or industrial use. For structural integrity, check the bursting strength to ensure the fabric can withstand tension without tearing.