I offer an interesting (about 100 slides) presentation on the history of ear trumpets.
The lecture is based on my Guinness World Record collection of acoustic ear trumpets and a huge resource of associated ephemera.
The process usually takes about 45 mins but can get longer with interrupting questions.
I have over 500 slides to choose from, so the presentation can be changed to meet local needs.
My fee is £200 plus travel,
A shortened version (10mins) is available for charitable institutions.