Not all PVC windows are of the same quality and it is easy to understand the profile classification by looking at the letters and numbers embedded in the PVC profile. 

1️⃣ Severe or Moderate Climate: the Iberian Peninsula is classified as a severe climate, so a good profile must have the letter S.

2️⃣ Class I and II ascertain the resistance to impact and the height of fall; also to determine if it can withstand hits caused by stones, hail, etc. Our profile is class II.

3️⃣ Class A, B or C refers to wall thickness. The best, ours, is A and it stands for thickness higher than or equal to 2.8 mm