Cal. Rev. & Tax. Code § 6369.2

There are exempted from the taxes imposed by this part the gross receipts from the sale of and the storage, use, or other consumption in this state of wheelchairs, crutches, canes, quad canes, white canes used by the legally blind, and walkers, and replacement parts for these devices, when sold to an individual for the personal use of that individual as directed by a physician.