FILTER SOCKS Sale! from 870 /per Size 4 inch 7 inch Qty. Add to Cart This item is currently on backorder but you can still purchase it now and we'll ship as soon as more become available. 300-micron filter socks. Fits all LUNA sumps. Choose 4 or 7 inch. Made in the USA. FREE SHIPPING within the Continental US for orders over $100 . . .