Water Sentinel WSW-1 replacement filter for the Whirlpool 4396508 refrigerator. Brand New. 

Boxes never opened. 

Also compatible with the following models:

Whirlpool: 4396508, 4396510, 8212491, 4392857
Kitchenaid: 4396163, 4396547, 8212491
Kenmore: 46-9010, 46-9902, 46-9908