A Repair Kit
Repair Kits can be found in some of the Guild Hall maps during a GvG match. They are used to repair the Catapults on the island. These are located at pre-determined locations on the map.
Repair Kits can also be found during the Alliance Battle maps, Kaanai Canyon and Ancestral Lands. They are used to repair the gates to the centre fort by the defending team. They are acquired at Equipment Stations.
To repair a structure, hold the repair kit, and click the lever or gate lock located next to the structure to repair it.