I'm looking for a 50 mW 532 nm laser pointer with a power supply for demonstration purposes for a lab that I'm teaching and I was hoping to get some recommendations from you guys. We're only going to use these lasers to show basic properties, so we don't need anything extremely expensive ($100-$500 max). I had initially purchased a pair of lasers from Laserbtb, but they emailed me back a week later telling me that they no longer offer that laser. Other companies seem to want way too much money for a 50 mW laser. I've found plenty without a power supply, but since this is for a class, we'd rather not have to worry about batteries too much. If you guys have any suggestions, please let me know. Thank you in advance for your help.