The Hosrivae Water Softener Position Switch Replacement is an essential component for any Ws21x10003 water softener system, designed to ensure optimal functionality and longevity. This replacement valve position sensor, 0.46 x 0.98 x 0.39 inches in black, has been engineered to fit seamlessly into your system, providing precise control over the softener's brine and calcium/magnesium regeneration cycles. Its sturdy construction ensures reliability in demanding environments, while the included mounting screws allow for straightforward installation. This product's unique design, combined with its superior quality and excellent customer service, make it a top choice for water softener professionals and homeowners alike.