Three industrial workshop stools from the 50s/60s

Rare set of 3 workshop stools with backrest, from the 50s/60s, in metal, and wooden seat, resting on 3 legs and adjustable in height. Ultra resistant, they came from an old workshop in auvergne. Originally, they must have all had a classic blue paint, which, over time, has disappeared to give way to a pretty blue and metal patina. They therefore rest on 3 legs, one of which also has an arch around it to rest its feet. 1 has a black plastic wheel so that the stool can be raised or lowered to its size and 2 others just have a crank system to turn. They have all been revised, are all functional, can be used as a low stool with a low seat height of 50cm or mounted with a high seat height of 68cm for 2 and 60cm for 1. They have of course, a patina due to age and initials and inscriptions on the backs, which probably corresponded to the names of the workers of the time  they weigh about 6kg each. They are therefore very robust, stable and today ideal for making a functional decoration for craftsmen, shops, restaurants, guest houses.