A Heavy Duty replacement grease-able track rod end ball joint with a RH thread.
Most track rod ends are sealed for life but this can be a short life if you do any off-roading. A quick regular squirt of grease will ensure these track rod ends last a long time.
The track rod ends are handed, they have either a RH thread or a LH thread.
Please note some models have 3 track rod ends fitted and 1 ball joint on the steering box drop arm.

Land Rover: Discovery 1, All Models, 1989-1998, RH Thread