Testicle Keychain by I Heart Guts Let it all hang out with the cutest testicle keychain ever. Engraved back of keychain and display read: "Testicle: Having a Ball" Testicular facts grace the cardboard backing. Zinc alloy with soft enamel, testicle measures 1.93" x 1.9". I Heart Guts puts a smile on your face and smarts in your brain.