On Friday, infant-testing medical-equipment maker Natus Medical (NASDAQ:BABY) announced that it has acquired Astro-Med (NASDAQ:ALOT) subsidiary and neurophysiological recording instruments manufacturer Grass Technologies Product Group. Grass specializes in the production of polysomnography and electroencephalography systems used in both clinical and research work.

In a press release on the acquisition, Natus clarified that it paid $18.6 million cash for Grass, or almost precisely the company's annual sales of $18.5 million. That represents a sizable discount to the 1.4 sales ratio Natus' own shares fetch.

Natus expects the acquisition to quickly become accretive on a pro forma basis, adding to earnings in both Q2 and full-year 2013.

Investors reacted positively to the news, bidding Natus shares up 1.8% Friday to close at $12.54.