That is to check the outer layer of the A/C Hose, the thick wall is Standard Barrier A/C Hose, the thin wall is Reduced barrier A/C Hose.

Replacing a power steering hose in a Ford Focus can vary in complexity depending on the specific model and year of the vehicle. In some cases, it may be a relatively straightforward DIY job for those with the necessary tools and mechanical skills. However, in other cases, it may be best left to a professional mechanic to ensure the job is done correctly and safely.