Monos Metro Sling Vegan Leather in Saddle Tan (Brand New Without Tags) Crafted with water-resistant, ultra-microfiber vegan leather, the compact and functional Metro Sling is a crossbody bag made for life on the go.  This bag has interior pockets with an integrated keychain carabiner. And the versatile single-strap design, the Metro Sling can be worn across your body or slung over one shoulder.