The push button or plunger actuated PB series was developed as a direct replacement of an existing and problematic mechanical type contact. The PBF flange push button can be installed without re-drilling or redesigning the original installation. The sealed contacts of the reed switch insure a long service life. Plunger actuated reed switches have become so popular on new installations that many variations are now being produced. The PB-100 is a press fit design and eliminates the screw mounted flange. A terminal connection is offered on most models and this option can be added by including a T at the end of the part number - for example PB-100-T.