it is the same as this one. http://www.amazon.com/Mechanical-Sample-Qu...k/dp/1932613366
it is just like new, no marks.
ask for 25$+shipping, or best offer.
if you are interested please let me know.
you can send email to [email protected]
Thank you
check the ashrea 62.1, there is a table, you can get the information for a 7-grade class room, how many student per sqft. you already know the square footage, so you can get the total students in that space.