A changeover reed switch has three contact leads. Form C or double throw switch described the switching function as break-before-make. The switching sequence is as follows. One contact opens its connection to another contact and then closes its connection to a third contact. Furthermore contact configuration is the number of switches or poles used in a component. So a single pole double throw (SPDT) device contains a single changeover switch. Likewise double pole double throw (DPDT) contains to 2 changeover switches in a component. Finally changeover reed switches can also be used in a normally closed or Form B contact configuration. Standex offers a 100 watt high power KSK-1C10 switch for changeover applications. And for even greater versatility the ORT551 series form C changeover switch meets most application requirements. We package the ORT551 series in one of two ways. One is a miniature 14mm bare glass surface mount version MK23-90. And the second version is the environmentally sealed SMD MK01 series. Furthermore both series come in tape and reel packaging per IEC 286/part 3 standards. So manufacturing is easy with pick and place automation. Standex Electronics also integrates the ORT551 into various standard sensor and reed relay series.