specialized in sampling equipments such as gas sample bags,liquid and solid sample bags,sample pumps,gas sample vacuum chambers. According to E-Switch brand design concept,we have developed our own dedicated flow-adjustable multi-functional valves,Teflon valves and gas nozzles which have won several national patents that allow no copy. E-Switch brand flow-adjustable multi-functional valves have the monst complete functions and interface sizes in this line and they can be applied to hoses with 3 to 6 mm in diameter.They don't leak even when taken for samples for *5 times, which is of number one priority in the industry. Our products are excellently air proof,quality stable and have obtainde patent. E-Switch brand gas sample bags are mainly mande from 4 films including aluminum foil,Tedlar PVF,Teflon FEP,polyvinyl fluoride PVDF.Valves are mainly made from 3 materials from 5ml to ***0 liters can be tailored to meet customers' requirements. Our products are popular at home and abroad.The application fields include automobile VOC detection,indoor and outdoor VOC detection, petroleum chemical industry, natural gas ,agriculture and research institution,colleges and universities and the third-party testing.