Easily your most important piece of equipment is...YOU! Make sure you're in full working order, and check your personal presentation carefully - if you don't, your audience will!
The overhead projector (OHP) displays overhead transparencies (OHTs or OHPTs). It has several advantages over the 35mm slide projector:
it can be used in daylight
the user can face the audience
the user can write or draw directly on the transparency while in use
The whiteboard (more rarely blackboard or greenboard) is a useful device for spontaneous writing - as in brainstorming, for example. For prepared material, the OHP might be more suitable.
The duster is used for cleaning the whiteboard. It is essential that the duster be clean to start with. You may consider carrying your own duster just in case.
Markers are used for writing on the whiteboard (delible - you can remove the ink) or flipchart (indelible - you cannot remove the ink). They are usually available in blue, red, black and green. Again, it's a good idea to carry a spare set of markers in case you are given some used ones which do not write well.
"A good workman never blames his tools."
The flipchart consists of several leaves of paper that you 'flip' or turn over. Some people prefer the flipchart to the whiteboard, but its use is limited to smaller presentations.
The Slide projector - which must be used in a darkened room - adds a certain drama. Some slide projectors can be synchronised with audio for audio-visual (AV) presentations. These projectors are typically used for larger presentations. The majority take 35mm slides or transparencies (as seen here), but projectors for 6x6cm slides are also available.
Transparencies are projected by an overhead projector or a slide projector onto a screen - in this case a folding screen which can be packed up and transported.
The notebook computer is increasingly being used to display graphics during presentations. It is often used in conjunction with an overhead projector, which actually projects the image from the computer screen onto the wall screen.
Handouts are any documents or samples that you 'hand out' or distribute to your audience. Note that it is not usually a good idea to distribute handouts before your presentation. The audience will read the handouts instead of listening to you.