Pulse-mass mine

Pulsemass Mines were a weapon created by the Hapes Consortium to prevent enemy vessels from escaping into Hyperspace during combat. It used the same techniques as Gravity well projectors used by Imperial Interdictor cruisers. However, unlike interdictor crusiers, these mines prevented either side from jumping to hyperspace for 10 to 15 minutes.

Appearances
The Courtship of Princess Leia