Welch DryFast PTFE Diaphragm Vacuum Pumps enable precise vacuum control for organic evaporations with exclusive Advanced Vapor Management (AVM). Oil-Free, portable, chemical resistant, dual head diaphragm design simplifies maintenance. Choose from seven dry PTFE vacuum pump models with flows up to 70 L / min and adjustable vacuum down to 2 Torr. Economical DryFast vacuum pumps are perfect for tough lab applications.