Current market price, limit price, and short term volatility define the probability that the market price will reach the desired limit price and that the order will be executed. Component signals are respectively obtained from constituent signals. A small cylindrical magnet having a size larger than the outer diameter of the level difference portion but smaller than the outermost diameter of the ferrule is connected to the level difference portion. Certain embodiments include elements for maintaining and restoring cushioning capability of through holes when subjected to compressive, deforming forces.