An 50hz hum with a slight buzz on it. Created on Reaper Tone Generator. EDIT: I notice a lot of folks have downloaded this, if you'd like to give a donation so I can make more stuff then I'd be super grateful! Thank you <a href="https://donate.stripe.com/6oE28f4HTbMVa3e4gg" rel="nofollow">https://donate.stripe.com/6oE28f4HTbMVa3e4gg</a>