3M Co. has sold its unit that makes fiber optics and other materials for the telecommunications industry for $870 million.

Corning Inc. bought the Communications Markets Division, which also includes the copper passive connectivity units and the xDSL, FTTx and structured cabling solutions products, officials said Monday.

One shard of the transaction remains pending. 3M said the sale of its telecommunications system integration services business in Hannover, Germany, won't be completed until the end of 2018.

It is expected to sell for about $30 million.

In all, 3M's Communication Markets Division had annual sales of about $400 million.

3M expects to realize a 2018 net earnings-benefit from the divestiture of about 40 to 45 cents per share.

3M announced in December that it would sell the division to Corning. At the time, Ashish Khandpur, 3M's executive vice president of electronics and energy, said the fiber optics and copper connectivity business was no longer seen as a core business for Maplewood-based 3M.

3M has conducted several strategic reviews and sold off a number of businesses in the last three years that it no longer deems central to its growth mission.

The sales helped 3M re-funnel its efforts into higher growth businesses such as its large Capital Safety and Scott Safety acquisitions and into developing new products related to auto electrification, respiratory health, and safety and graphics.