This is a 1927 US Number 4 outfit. The brown wood box was last used in 1927; the wood box was painted green starting in 1928.
Colors had been introduced in 1926, but only a few parts were painted red or green. More colored parts were added in 1927, but the strips (and derived parts, such as Double Angle Strips) were not painted in the US (at least not until the 1937-1937 blue and gold outfits). US strips were apparently tinplated starting in 1922. They continued to be tinplated through the Gilbert era, at least through 1935.