This is a rugged work chair series for demanding environments. Robust and stable work chairs that can withstand extraordinary strain, e.g. at schools. The RBM 300 series has been designed to endure many different users over a long period of time. All chairs in the RBM 300 series have freely adjustable seats and backs. Simple and uncomplicated. Several of the models are safe for school use: They require special tools to dismantle the back support and adjustment.