Genuine Daikin 380116J Outdoor Accumulator Cushion Rubber is the cushion rubber that supports and isolates the accumulator in the outdoor unit, damping vibration so it isn't passed into the casing and pipework. When it perishes or goes missing, the accumulator can vibrate, rattle, or stress its connecting pipes. A genuine cushion rubber locates and damps the way your Daikin expects — where a non-genuine part can let the accumulator move and add noise.