Yes, air guitar strings. Bags of oxygen sold by KISS. If you for some weird reason want to buy them, they're $ 3.99 but ... only available in Las Vegas ... (ofcourse).
"These strings are precision manufactured to the highest standards and most exacting specifications to ensure consistency, optimum performance, and long life. KISS Air Guitar Strings are made from nothing wrapped around more nothing, with specially tempered nothing-plated high carbon nothing, producing a well-balanced tone for your air guitar. Gauges .000, .000, .000, .000, .000, and .000. And best of all, they’re only four bucks for a pack of none! WHAT AN AMAZING VALUE!!! That’s a great use of four dollars and is definitely not just throwing your money away."