How do you put oil in koken barber chair?

To add oil to a Koken barber chair, first locate the hydraulic pump mechanism, typically found beneath the seat. Use a suitable hydraulic oil and fill the pump through the designated oil port, which may require removing a cap or plug. Be careful not to overfill, and ensure the chair is in a stable position while you work. Once filled, check for any leaks and test the chair's operation before using it.