① Diameter of metal plate
② Material of metal plate:
B: Brass S: Stainless Steel
N: Nickel T: Tin P: Phosphorus bronze
③ 2: Double ceramic plate H: Special type
④ Resonant frequency ( Unit: 1000Hz )
⑤ T: Thin type Omitted: General type
⑥ Driving type E: External drive S: Self drive
⑦ Feedback electrode shape |