I saw this kind of lamp in http://www.classpad.org/catalog/
named as Ultra-Optics BK-FLMBX light and costs 10$;
however, u can find it on other online store more cheap i.e. 7.8 $

Just make a search on Google

It uses 2X "AAA' size batteries.
I khow that it closely fits to classpad.
I'm planning to buy one but I couldn't find it in my country.

I don't khow how/where.
