Sandstone PBR texture is a texture pack. It contains a ZIP format archive with the following maps:
Ambient occlusion 4096 x 4096 (png, exr)
Base color 4096 x 4096 (png, exr)
Roughness 4096 x 4096 (png, exr)
Normal 4096 x 4096 (png, exr)
Height 4096 x 4096 (png, exr)