The SRP-AM2 Head Holding Device, MRI measurement-compatible, can be attached to SR series fixing devices. Such attachment ensures extremely stable fixation of the head. When the instrument is detached for MRI measurement, 100% of the instrument becomes plastic to make the procedure easier. Once MRI measurements are completed, the instrument can easily revert to its function as a fixing instrument, while keeping the animals fixed. Two types are available: SRP-AM2 Head Holding Device for mice, and SRP-AR2 Head Holding Device for rats.