Mill Rock Capital, a growth and operations oriented private investment firm, completed the investment in DRT Holdings, a manufacturer of specialized components, precision tools and container systems. Financial terms were not disclosed. "DRT's core value proposition of highly complex machining capabilities and superior customer service is more important than ever, and we look forward to expanding DRT's product and service offerings to our loyal customer base. Our partnership with Mill Rock provides the strategic resources and financial strength necessary to meet our customers' expanding needs," Gary Van Gundy, DRT CEO.