In the past Audio Note once used the Jensen made aluminium foil signal caps, offering a lower cost signal capacitor close to the tradition of Audio Note. Since those days have gone and Audio Note make their own capacitors they chose tin over aluminium as it provides a slightly more fluid and detailed sound.
These are 100% tin foil capacitors, the line is tin foil with a mylar dielectric in an aluminium can with 1mm solid silver leads. These offer an affordable alternative to the copper and silver foil types. Tolerance is 10%.