These are the threaded body coil-over struts that were used on the factory RSR race-cars.
The spindle is raised 19mm and reinforced to allow for lowering the car while still maintaining correct suspension geometry and fitting 15" wheels.
Shock dampening is 100 compression and 220 rebound.
Spring hats and a wide selection of coil springs are available separately, below. One pair includes both left and right sides and lower 2.25" spring seats.