This is a special 4mm vibration motor designed for low current / low power consumption.  It is normally mounted in a molded pocket in the shell of the products housing.   This motor is available with or without the PCB mounting bracket and is also available.  For minimum orders of 2000 pieces we can add a connector on the end of the wires.    If you need this motor without the rubber gasket please order S4Z08B037-55L  ( 17mm  leads )