The Magical Convergent Cannon: Jupiter is a powerful weapon feared by all. When fired, the cannon releases a compressed beam of energy that wreaks destruction wherever it passes. One blast from the cannon was enough to completely shatter Erza Scarlet's Adamantine Armor, an armor renowned for its extremely high defensive capabilities, to pieces. Had the armor not intercepted the blast, members of Fairy Tail feared that one blast from the cannon would be enough to completely annihilate their guild and the surrounding area. Additionally, the Magical Cannon has enough power to significantly damage a Giant-empowered Makarov Dreyar, who, in that form, is well known for his enhanced strength and durability; a further testament to the overwhelming destructive capabilities that Jupiter possesses.
The cannon in Phantom Lord's possession is a large, rusted metallic structure held together by many metal rods and bolts. The barrel of the cannon can be extendable. The muzzle of the cannon is completely metallic, and is obtusely shaped. In addition, aiding in the cannon's extension are four, long, metallic attachments hooked on to each side of the barrel.
The cannon in Grimoire Heart's possession is composed entirely of metal, unlike Phantom Lord's, and is shorter, with flat pieces of metal sticking out of the barrel at odd angles.
The power source for Jupiter is, fittingly, an extremely large, dark Lacrima, which is connected to by four other, smaller, Lacrima that transfer Magic Power to the aforementioned larger one, which in turn, are connected to the floor and ceiling of its station, feeding Magic Power into the cannon. The recharge time for the Magical Convergent Cannon: Jupiter in Phantom Lord's possession is fifteen minutes. The recharge time for the cannon in Grimoire Heart's possession, if one exists, is unknown.