Self-inking stamp parts (Surrey Hills)

From left to right in main picture:
1) spare characters (red) and tweezers (no stamp for these)
2) self-inking stamp with some characters (grey)
3) self-inking stamp with custom design, and self-inking stamp ink refill.

The red characters have a flat back. The grey characters have little stubs at the back which fit into the ridges of stamp (2).