The NTE6403 is a silicon planer, monolithic integrated circuit having the electrical characteristics of a bilateral thyristor. This device is designed to switch at 8 volts with a 0.02%/°C temperature coefficient and excellently matched characteristics in both directions. A gate lead is provided to eliminate rate effect and to obtain triggering at lower voltages. The NTE6403 is specifically designed and characterized for applications where stability of switching voltage over a wide temperature range and well matched bilateral characteristics are an asset. It is ideally suited for half wave and full wave triggering in low voltage SCR and TRIAC phase control circuits.
 
Full spec sheet:
https://www.nteinc.com/specs/6400to6499/pdf/nte6403.pdf