See some testing pictures in Intertek Lab, we tested PVC Awning Windows, PVC Fixed Windows, PVC Sliding Windows, PVC Tilt & Turn Windows, PVC Sliding Doors as per AS2047-2014. All is German ROTO Lock System and Double Glass.
A lot of people think the goods is cheaper and bad from China. Yes, some Chinese suppliers make bad quality goods and low price, so a lot of people complain the goods is bad, and think the goods always is bad from China.
Look! usually the corner window is with mullion, now the new style sliding window is without mullion. this is for outside area to save your space.