The Luminos is a simple solution for teachers who need the ability to write and erase throughout their presentations in small sized classes and training rooms with dim lighting.Open head container with highest quality single or triplet lens (not closed head as incorrectly printed in 2006 catalog) swivels 360 degrees so light does not have to shine in presenter"s eyesAdjustable display angle up to 60 degrees helps avoid "keystoning"Focus knob on folding arm for easy storageRest stop for overhead lamp while shipping or during storageHigh/Low switch for brightness vs lamp lifeLamp changer for uninterrupted use if lamp burns out during presentationRugged ABS plastic withstands knocks of daily classroom useBreak resistant glass means less classroom interruptions and repairsThree year warranty (not one year warranty as incorrectly printed in 2006 catalog) for educational uses unlike other products purchased from consumer electronics stores whose warranties would be voided if used in schools.