[dizka (OP)]

How to choose a suitable profile
When talking about a profile, they often draw an analogy with the window skeleton. This complex structure of plastic and metal has several cavities-chambers-separated by sealed partitions. Their number affects the strength of the window, the ability to retain heat. For the manufacture of window profiles Tilt and Turn Windows newbielink:https://glawindows.com/tilt-turn-windows/ [nonactive]
The reasons why this type of plastic is used:

ability to withstand adverse conditions;
low thermal conductivity;
cheapness;
ecological safety;
preservation of consumer properties for a period of at least 50 years;
reliable noise insulation.
The usual color of PVC is white, but there are multi-colored profiles, as well as laminated for different types of wood.

After examining the plastic, you can determine how well the window frame will serve. High-quality PVC — absolutely smooth, monolithic, homogeneous material. The presence of spots and grains is eloquent evidence of forgery.