The thongs have lightweight, water-resistant batteries that, when fully charged, illuminate the straps for two hours in various neon colors, including blue, pink and yellow. Wearers can use a wall adapter to charge them up, but car chargers are available for those on the go.
They use batteries, that’s why.
Oh and I almost forgot…
I wonder how you use the car charger? :think: LOL. Imagine ... you get in the car and then all of a sudden your friend unzips her pants ...... then looks at you and says. “What?? I need to recharge my thong.” 😛 :lol: