Lenovo Flex 15 Slot-In Sleeve, Black (GX40H55183) Dedicated port openings allow you to use all of your connected devices with the covering in place. Form-fitting sleeve ensures a precise fit for your Flex 3 2-in-1 Protect your Flex 3 Multi-Mode notebook in all of it's modes. Flex 3 15 Slot-In Sleeve (Black)