From Halopedia, the Halo wiki
Post-Covenant War conflicts
The SS-1000 Sabre was a Space fighter in service with the UNSC.
Following the end of the Human-Covenant War but before the Created conflict, the SS-1000 was secretively put into limited production and then deployed to important UNSC sites.
SS-1000 Sabres were part of the 22nd First Response Wing.