Teak mirror with ledge. It was purchased in Copenhagen, I believe, in the 1960s. It has been since been re-stained a slightly darker shade of brown. Tongue and groove corners. Very good condition, but not perfect. It could be the same as this one: https://www.1stdibs.com/furniture/mirrors/pier-mirrors-console-mirrors/midcentury-danish-modern-teak-mirror-shelf/id-f_34426222/

17.5 wide x 29.5 high x 1.5 inches deep and 5 inches deep at the bottom with the ledge