CER-1/4-20 Ceramic Terminal Bases and Caps offer high temperature insulating protection for standard screw terminals on mica heater bands, ceramic heater bands, mineral Insulated band heaters, channel heaters, finned strip heaters, and mica strip heaters. Ceramic terminal bases and caps help to provide an electrically safe environment in your manufacturing facility, and these high temperature bases are very easy to install. This ceramic terminal base (CER-1-4-20) mates with the Ceramic Cap pictured in the product image. The thread is 1/4" by 20. 5 SETS ARE INCLUDED, (ONE SET=ONE BASE AND ONE 1/4-20 THREADED CAP).