Private equity firm O2 Investment Partners LLC has acquired a majority interest in Greco Aluminum Railings Ltd., which makes welded-aluminum balcony railings.

O2, based in Bloomfiled Hills, Mich., focuses on acquiring a majority interest in small and middle-market manufacturing, niche distribution, select service and technology businesses. Its portfolio includes NH United, Silbond Corp. and RheTech. Terms of the deal were not disclosed. NH United delivers information technology training, Silbond is a commercial producer of tetra ethyl ortho silicate for the semiconductor industry and RheTech makes color concentrates.

Greco Aluminum, headquartered in Windsor, Ontario, installs railings in new construction and restoration projects for condominiums, apartment buildings, hospitality and senior-living facilities.