SR-9M-HT Stereotaxic Instruments are specifically designed for chronic experiments on mice. Fixation by the chamber frame permits repeated fixations in the same position in an unanesthetized state. Thereby chronic experiments as well as acute experiments are allowed without causing damage to the animal. The SR-9M-HT can be used for visual and/or auditory experiments. The head holding device can be removed from the base plate so it can be placed under a microscope. An AP frame bar is provided, to which many different types of accessories can be attached along with the attached micromanipulator: SMM Series (SMM-100 / SMM-200) or SM-15R/L.