- "It seems to have permanently disrupted communication between the individual cells, rendering each one inert. We explored such a technology in the past with no success."
The weapon is capable of severing the communication between the blocks of Replicators. They are the only weapon, besides conventional Tau'ri guns, capable to actually destroy a Replicator. However, the weapon can also sever the connections between the blocks of Human Form Replicators, whereas conventional projectile weapons cannot. The Asgard had previously experimented with a weapon that would do much the same thing, without success. The weapon discharges a blue energy wave. Other variants were created, including disruptor cannons, capable of wiping out any Replicator on a planetary scale, and a satellite variant, which can wipe out Replicator ships in space. (SG1: "New Order, Part 2", "Gemini")
The weapon was created by Colonel Jack O'Neill, from using the knowledge of the Ancients he once had after it was all downloaded into his mind via the Repository of knowledge. Though at the time he was in stasis, Thor, Daniel Jackson and Teal'c are able to communicate with him by using the Asgard computer. There, O'Neill was able to virtually create one via the same computer, though after his Ancient knowledge was flushed out of him, he had no idea what the device was, until a Human form Replicator in Thor's ship, Eighth tried to kill them, and P90s were ineffective. O'Neill picked one up and fired it at the Replicator, where he was destroyed. Thor later used the disruptor to create a disruptor cannon to destroy all Replicators on the surface of Orilla, their new colony. However, a small number of Replicators, led by Fifth managed to escape before the weapon activated. (SG1: "New Order, Part 2")
After learning that Fifth is heading straight for the Milky Way to take control of the galaxy, the Asgard were able to create a satellite variant and sent it to the Alpha Site, after learning that Fifth is on his way there. They upgraded it, since Replicator Carter made them believe that Fifth created a cipher to block the weapon, a claim later turned out to be false. The weapon worked, and activated by Replicator Carter, so she could eliminate her rival to control the Replicators herself. She managed to create her own cipher to render the disruptor technology useless. (SG1: "Gemini")
Eventually, the real Samantha Carter managed to overcome this with Thor's help. However, after the first shot, the Replicators, who were taking control of the majority of Anubis' forces adapted alarmingly quickly. In the end, they were able to simultaneously hit all the Replicators at once with the help of Jacob Carter and Ba'al, by reconfiguring the Ancient superweapon on Dakara to destroy them once and for all. (SG1: "Reckoning")
Sometime after the fall of the Replicators, and the encounter with the Asurans in Pegasus, Carter created an Earth version, which was named Anti-Replicator gun, though eventually, the Asurans soon managed to override it.
Behind the scenes
Knowing Richard Dean Anderson would play around with the disruptor, the model shop team who made the prop made it more robust, so it could not be easily damaged.