Truck Nutz is a brand name for the dangling plastic testicles some people affix to the bumpers or hitches of their vehicles. Also sold as Bulls Balls, Your Nutz, and other brand names, these plastic novelties have a powerful symbolic charge and are often associated with a crass, macho, red state audience. But truck nuts are a surprisingly complicated signifier whose symbolic power is increasingly divorced from their real-world usage.

On this episode, we talk to owners and users of truck nuts, investigate the origins of the accessories, and deconstruct the meaning of these oft-joked-about symbols. We’ll also take a tour of other novelty testicle products, including Bike Balls (testicular bike lights), Gunsticles (plastic testicles for guns), and Neuticles (prosthetic testicles for neutered pets), to better understand the maligned symbolism of truck nuts.

Links and further reading on some of the things we discussed on the show:

Ad for Monster Truck Nuts
Truck Nutz Prank Call
Elie Mystal’s writing on truck nuts for Above the Law
Austin Vasectomy in Austin Texas

This episode was written by Willa Paskin and edited and produced by Benjamin Frisch. Decoder Ring is produced by Katie Shepherd and Max Freedman. Evan Chung is our supervising producer.

If you have any cultural mysteries you want us to decode, email us at DecoderRing@slate.com. Or you can also call us now at our new Decoder Ring hotline at 347-460-7281. We love to hear any and all of your ideas for the show.

Want more Decoder Ring? Subscribe to Slate Plus to unlock exclusive bonus episodes. Plus, you’ll access ad-free listening across all your favorite Slate podcasts. Subscribe now on Apple Podcasts by clicking “Try Free” at the top of the Decoder Ring show page. Or, visit slate.com/decoderplus to get access wherever you listen.

Learn more about your ad choices. Visit megaphone.fm/adchoices