JIAWANSHUN Glass Vacuum Bell Jar with Base Vaccum Demonstration Kit Sound Physics Demonstration Vacuum Hood Disc Bell in Vacuum Laboratory Jar

It’s actually a pretty good vacuum bell but it needs to have the rubber ring glued to the bottom of the bell and trimmed. If there was a valve that vented to the outside while still attached to the base, that would be good.

I recently received a replacement for a defective order. The replacement works very well. This company responded quickly to my request for a replacement and they were very helpful. I highly recommend this company. They give excellent service for their products.

Bought this for demos in my middle school science class and rented a pump from the auto parts store. Couldn't get a perfect seal so we couldn't get the bell to silence, but we got water to boil and blew up marshmallows, so it was good enough.

This produce was purchased for a middle school science class. I was a parent that helped the teacher put this together. I was able to make it work as a vacuum cylinder but the problem I have with it is that it has many flaws. First it should have two valves, one to apply the vacuum to and one to allow the vacuum to be released. The way I had to work it was to cut an A/C hose and put it on the nipple connection at the base of the chamber. Run the vacuum and when done, disconnect the hose and release the valve. For a kids science classroom having to disconnect anything to release the vacuum is a potential. You shouldn't have to cut a perfectly good hose with connections on both ends to fit on the device. The device should come with a 1/4" connection at the valve to connect the vacuum pump to and a second valve to be able to release the vacuum.

It doesn't work. There is no apparent air flow through the blue base. I connect it to a vacuum pump and I get no noticeable vacuum. Seems to be a problem with the base.