Multi-adaptive shielding was a deflector shield stealth technology developed by Erin and Magnus Hansen in 2353, for use in keeping their vessel, the USS Raven, virtually invisible to Borg sensors during their field study of the Collective.
After tracking a Borg cube at close range for nearly three years, the Hansens encountered a subspace particle storm which caused their shielding to go offline for 13.2 seconds, during which time the Borg were able to detect them. Considering the Raven a threat, they pursued the ship and ultimately assimilated the Hansens.
In 2375, the crew of the USS Voyager incorporated multi-adaptive shielding into the systems of the Delta Flyer, to facilitate a rescue mission for Seven of Nine, who was being held captive by the Borg Queen in the Unicomplex. Although the shielding was initially successful in concealing the Flyer's presence, the Queen, who was able to use the Collective's knowledge of the technology due to the assimilation of the Hansens' research, was able to adapt and penetrate the shielding. Tom Paris, piloting the Flyer, managed to remodulate the shields to avoid further detection, prompting the Queen to lay down a blind firing pattern. The Borg were eventually able to lock on to the Flyer's shield modulators, continually adapting to the changing modulations. Boarding the Unicomplex, Captain Janeway managed to rescue Seven and escape on board the Flyer. (VOY: "Dark Frontier")