Tollan ion cannon

From The Stargate Omnipedia

Ioncannon.jpg

A powerful Tollan energy weapon used for planetary defense against incoming orbital attack. Cannons are located on the surface strategically around the planet to provide total coverage, with its energy projectiles capable of reaching ships in orbit.

Tollana is protected by a planetary network of cannons, which automatically track and destroy threatening ships in orbit. They can also be operated manually, using a small control panel on the side of the weapon.

KEY EPISODES

Pretense - With help from Lya, the Tollan ion cannon is successful at repelling Heru'ur's forces, as well as Zipacna's entourage, from orbit.
Between Two Fires - Having previously refused to share their advanced technology, the Tollan Curia offers Earth their ion cannon technology in exchange for pure trinium.