Numerex is acquiring Airdesk, a rival in the provision of machine-to-machine solutions for such things as vehicle tracking, in a deal worth $5.5 million.

Numerex (Nasdaq: NMRX) said it was paying $4 million in stock and debt assumption for Airdesk. The deal also includes a $1.5 million earn-out for Airdesk.

Airdesk has more than 300,000 customers.