Sealing rings for Tesla S air struts, 2012-16 pre-facelift models.
They fit front and rear, both on RWD and AWD variants.
The set consist of three rings: A rubber (1) 'O-ring' that seals the transition and prevent leaks. A (2) 'support-ring' in metal, that covers a C-shaped (3) 'stop-ring', also of metal, and an air nipple as well.
Note that the strut itself must be dismantled to get 2 and 3 in place, and that they cannot be pulled over the lower bolt attachment.
Sold as a set only.
We also recommend that you pressure test the shocks once the repair is complete, see link.