Chairs of the Ray Soft collection from Brunner with a Four-Legged Frame Oak base (wooden). In three versions: low, medium and high back. The base is presented in three colors: oak, light oak, black oak.

Links to the manufacturer's website / store:
Low back: https://www.brunner-group.com/en-DE/products/details/ray-soft_9613/A/ 
Medium back: https://www.brunner-group.com/en-DE/products/details/ray-soft_9623/A/ 
High back: https://www.brunner-group.com/en-DE/products/details/ray-soft_9633/A/ 

On the seat applied modifier TurboSmooth. For all models, a sweep.