Tech 21 gear is used by Kurt Cobain.

Tech 21 is a New York based manufacturer of guitar and bass effect pedals, amps, and DI boxes which allow the user to emulate the tone of many popular guitar amps and record those sounds directly into a mixer. Tech 21's core product, the SansAmp, was designed by Andrew Barta and introduced in 1989. The SansAmp (from French: sans ampli, "without an amp") is an analog effects pedal emulating a variety of different guitar amplifiers and speakers and enables recording direct to a mixing console.

Source: Wikipedia — Tech 21, licensed under CC BY-SA 4.0.

Effects