The 3690 is 70% lighter than other industrial vacuums with similar performance. The 3690  will supply all the power you need in a light weight portable package. The 3690 uses Pulse- Bac’s Automatic Pulse-Clean technology, complying with the 2017 OSHA regulations that  require a “back flush filter cleaning cycle” when using vacuums with materials that contain  Silica, this technology keeps the filters clean and clear, so suction stays consistent. The fully  automatic system features HEPA filtration that does not require the user to stop work to push  a button or shake a plunger; there is no disconnecting the hose to seal the vacuum inlet and  no compressor or other equipment to add extra weight.