OP-Ai Platinum Xrest 4D+ Massage Chair by Osaki Find repose under the robust influence of attuned shoulder massage, 4 different 4D adjustment levels to reach every ache, and all automatic and manual modes at your back and call with the use of the Osaki Premium Xrest app or through Alexa. Gain a unique state of amenity with the new OP-Xrest 4D. Thorough Shoulder Massage The OP-Xrest 4D incorporates an air bag compression system to give a meticulous massage to your shoulders and neck.