(1) The tax levied by RCW
82.08.020 does not apply to the sale of mobility enhancing equipment for use by or for a complex needs patient to meet the user's specific and unique medical, physical, and functional needs and capacities for basic activities when medically necessary to prevent hospitalization or institutionalization of the complex needs patient.
(2) In order to claim an exemption under this section, the purchaser must provide the seller with an exemption certificate in a form and manner prescribed by the department. The seller must retain a copy of the certificate for the seller's files.
(3) For the purposes of this section, "complex needs patient" has the same meaning as in RCW
74.09.557.