Triple-seal HD943 and HDL943 oil-free reciprocating gas compressors from Blackmer, part of PSG, a Dover company, feature a double-distance piece design with three individual sets of packing to prevent oil migration and maintain product purity. The compressors feature high-efficiency ductile iron valves with PEEK valve plates, ductile iron head and cylinders, three sets of self-adjusting filled PTFE packing sets on each piston rod for maximum leakage control, self-lubricating PTFE piston rings, precision-ground crankshaft and pressure-lubricated crankcase. 616/241-1611; www.blackmer.com.