How about the quality of the piezo element with PVC Diaphragm? FBelec supplies 35mm copper piezoelectric diaphragms pasted with 47mm PVC film welding wire, Piezo Ceramic Generator, tram alarm piece, high temperature resistant material or ordinary material, which can be made into conical or flat film. The length of welding wire can be customized, and the color of wire can be various colors, including red, blue, black, yellow, etc. Piezo Ceramic Bimorph can also be self excited or other excited. Glue dispensing at the welding position can prevent the welding wire from falling off! Quality assurance! If necessary, you can also apply green oil on the surface of the Piezo-Electric Diaphragm to prevent the oxidation of the piezo UNIMORPH after a long time and affect the use!