Genuine Leica Lens Hood Cap E39 ・ITDOO ・IROOA ・IUFOO ・12585 This cap is perfect for storing E39 lens hoods. Also recommended for those who want to protect their lens even when the lens hood is attached. I personally prefer it to the slip-on type because you can still see the lens hood's engraving. The uniformity of using a genuine product is also nice. However, unlike the slip-on type, there's no worry of it coming off, but please note that it cannot be attached if you have a lens filter on. The hood cap itself is Φ42mm. I think Leica products will become more and more rare over time. Please consider purchasing one. Thank you for viewing.