What am I?

Cover the clues so you can only see number one. How many clues do you need before you know the answer?

1. I am about 30cm high
2. People used me in the days before email.
3. Moving my handle squeezes another part together.
4. I could be useful in the days before sticky envelopes.
5. What I made could be seen on letters and documents from the Inglewood Council.
6. Kings and Queens also once used ones like me.

Answer in next week's TreasureLink.