The Model 3100E is an electric, float-operated switch which can be used as a high or low level alarm or for liquid level control. The 3100E is rated for high pressure applications, and the polystyrene float will effectively and consistently operate the switch at specific gravities as low as 0.50. The switch can be mounted directly onto the vessel nozzle or into an external float chamber. The Model 3100P and 3100P1 are pneumatic, float-operated switches for liquid level control. The 3100P is a 2-way normally-open or normally-closed switch and the 3100P1 is a 3-way block-and-bleed switch. The 3100P and 3100P1 are rated for high pressure applications, and the polystyrene float will effectively and consistently operate the switch at specific gravities as low as 0.50. Both models can be mounted directly onto the vessel nozzle or into an external float chamber.