The original Welch 2052 is a full chemical-resistant (not like its cheaper version), 4-head, oil-free dry diaphragm vacuum pump with all-PTFE contact surfaces and deep vacuum capability. Oil-Free, portable, full chemical-resistant, means less maintenance and no more frequent and costly oil change, or cross contamination. Ai is now the official dealer of Welch vacuum pumps. These pumps are made in Germany with one year warranty and technical support from Welch Vacuum. Free three feet 3/8" white premium food grade silicone vacuum tubing ($19.99 value) included.