I believe that I sell 10-3 UF by the foot. UF is meant to be direct buried. It'll work the same as Romex (NM), it just won't pass code or inspection. Home Depot.
Also sell 10-4 SO by the foot. All 4 wires are coated, where 10-3 NM is 3 covered and 1 bare.
Also sell 10-4 SO by the foot. All 4 wires are coated, where 10-3 NM is 3 covered and 1 bare.