Norcold Front Optical Board 638997 (fits the NX641, NXA641, NX841, and NXA841) Fits these Norcold refrigerator models:NX641 / NXA641 series: NX641, NX641IM, NX641.3, NXA641, NXA641L, NXA641R, NXA641IM, NXA641IMR, NXA641.3, NXA641.3RNX841 / NXA841 series: NX841, NX841IM, NX841.3, NXA841, NXA841L, NXA... See More