These Speedy Fineline End Stops are those which are used in conjunction with a glider. They end stop and glider are slide into the end of the curtain track such that the glider is trapped in the end stop. The last curtain hook is secured to the glider in the end stop preventing the curtain from coming off the end of the rail, or being drawn away from it.
NOTE these are handed, left and right.
Originally they came in three colours:
NOTE sold in quantities of 1 pair, photo for illustration.