Clicking on the FILTERS option in the INVENTORY > SKU page will reflect the above on the right side of the page. Below-mentioned are the uses of these filters-
SKU Type – You can filter the SKU by the classification assigned to them. You can also look check the 'Display unclassified' field and see the unclassified SKUs.
Purchase Type – You can either look at items out of the list of SKUs which have been purchased in the outlet or look at all the listed SKUs.
Recipe Filter – You can either look at items that are not used in recipes or look at all the listed SKUs. Checking the first option will exclude the Non-Food SKUs.