Permira is the European-based private equity firm that has gradually bought an 85 percent stake in Rodenstock. The same fund has now agreed to acquire Aearo Technologies, a U.S. company based in Indianapolis that designs and produces personal protective products and energy-absorbing composites. Aearo's holdings include a prescription safety eyewear operation that posted sales of $39.4 million in 2005, representing roughly 9.3 percent of total turnover.

Aearo's brand portfolio includes the likes of AOSafety, E-A-R, Peltor and SafeWaze. The company had revenues of more than $420 million last year. Permira is paying about $765 million for the company, in which Bear Stearns Merchant Banking currently owns a majority stake, along with an investment group and the company's management. After the acquisition, Aearo's management will own about 10 percent of the new holding company and will be offered additional ownership through an option plan.