2SK4037(TE12L,Q) by Toshiba is a rf mosfet transistors designed for reliable performance in electronic applications. It is widely used in industrial, automotive, and power management systems.

Discrete semiconductor products include individual transistors, diodes, and thyristors, as well as small arrays of such composed of two, three, four, or some other small number of similar devices within a single package. They are most commonly used for constructing circuits with considerable voltage or current stress, or for realizing very basic circuit functions.