The HEPA filter cover is vastly superior to the prefilters of other HEPA vacuums, While they capture particles down to 1, 0 micron, our HEPA filter cover captures particles HALF that size, down to 0, 5 micron, That makes a huge difference when you want to get the maximum mileage out of your HEPA filter, Greatly extends the life of a HEPA Filter, Machine washable, Dimensions: 10, 5L x 3, 5H x 10, 5W, SKU: DTLS005