1. Single handle controls double-layer window, handle rotates 90 degree glass fan 

  in single opening, rotates to 180 degree glass fan inside inverted ventilation, then 

  rotates to 270 degree position double fan inside opening, aluminum alloy window 

  handle, surface all aluminum structure, oxidation treatment process.

2. Double anti-misoperation accessories to avoid hardware damage due to wrong 

  operation.

3. Adjustable rolling lock point design, lock open more smooth.

4. High toughness plastic drive bar with lock rod, more quiet in use.