Review on 🔧 NewPosition 4CFM 1/3HP Air Vacuum Pump: Ultimate HVAC A/C Refrigeration Tool Kit for AC and Auto Repair with Manifold Gauge Set, R134A R22 Compatibility, and 3 Hoses by Joshua Albright

It works fine at first but as it heats up it loses the ability to create a good vacuum. I was never able to pull it below 600 microns and as the device warmed up it seemed to land at around 1200 microns. If I let it cool for 30 minutes I was able to pull out 750 microns. This is probably fine for most automotive work, but for HVAC you need to pull less than 1000 microns to evaporate moisture and 400 microns is a very common vacuum test level.