They are hella horn sharptones. I bought them as an inexpensive mod that I thought might would look good. But living in Texas, with large highway and hugs trucks, a louder horn definitely comes in handy on small cars.
Edit: Hella 922.000-731 Sharptone Horn Kit https://www.amazon.com/dp/B00R3O0Y0M/ref=cm_sw_r_cp_apa_sD4.yb1NX31YP
I like these:
https://smile.amazon.com/HELLA-H31000001-Sharptone-Yellow-Protective/dp/B00R3O0Y0M
And you'll also want a relay harness:
https://smile.amazon.com/Wolo-MCHWK-2-Air-Horn-Wiring/dp/B005I4DNP2
I put a set of these on my leaf in the factory horn location, and I'm very happy with them.