The Demo Slide viewing tube is about 100mm long, of which some 75mm is dedicated to storage of the culture, while the remaining 25mm is tapered to create an observation chamber suitable for microscopic examination.
A mere swing of the arm creates enough centrifugal force to put a more than adequate number of specimens in the observation chamber for observation under the microscope lens.
This is a great tool if you are short of time or wish to avoid frustrated students trying to make wet mounts with slides and coverslips.