The P.W.A.R.W, also known as the Planet Wide Anti-Replicator Weapon, is a type of weapon developed by the Tau'ri.
These weapons were constructed from knowledge known about the weapon that Colonel Jack O'Neill constructed from the Ancient Repository of Knowledge to combat the Replicator threat.
An Asgard designed satellite was used as the basis for a planetary based version of the weapon system designed to nullify the nano-cells of the nanites that made up the Asurans. However, the weapon had not been completed the design when a first strike was made by the Apollo against Asuras. (Cite|SGA|First Strike)