WatchGuard, makers of multi-function security devices for branch offices, is accepting a deal to be bought by a private investment firm.

The deal, worth $US151 million in cash, would make the company a property of Francisco Partners, a $US5 billion private equity fund that specialises in technology companies. Francisco would pay $US4.25 per share for WatchGuard if shareholders agree to the deal.

The buyout had the potential to give the company a better financial base, WatchGuard CEO, Ed Borey, said. The company lost $US8.2 million in 2005.

WatchGuard makes Firebox security appliances that support firewall, VPN, traffic shaping, Web filtering, virus screening and WAN failover. Some models include wireless access points to establish wireless LANs in branch offices.

One key characteristic of the gear is that it can be upgraded via software licenses to support more simultaneous users. Prices for the equipment start at $US480.

Borey said if WatchGuard was bought, it would not change the company's product strategy.

"It's business as usual," he said.

Once the deal is completed, which will probably happen in the fourth quarter, Francisco will have the right to keep or change the management team.

In filings with the Security and Exchange Commission, WatchGuard lists as its competitors Check Point, Cisco, Fortinet, Juniper, Nokia SonicWall and Symantec.