Review on Huanyu Oilless Diaphragm Vacuum Pump Oil Free Anticorrosive Pump 30L/Min Lab R&D For Filtration Extraction Apsorption 110V (Ordinary Type, GM-0.5A(Single Pump)) by James Kelley

It only pulls around 25in vac but it pulls it fairly fast. We use ours on a 50L rotovap and from this pump we then have a welch rotary vane pump. The great thing about this pump is it gives the ability to connect another pump in series which allows deeper vacuum and we can pull it faster. Great thing about this kind of pump is it's not affected much by any condensate or contaminants that make it to the pump. Unlike an oil based pump. Also the pump is fairly quiet once it's pulled a little vacuum and then just gets quieter. No issues starting either. If you don't need an extreme deep vac but a fast moderate vac that isn't affected by materials under vac then this pump may work for you.