You're exactly right. It's just a band that goes around the belly, like a belt would. What they're describing sounds more like a diaper that females would use.
Just FYI, I was in the market for belly bands last week and my local store wanted $24 for one.
You can order excellent ones from YT members or online for MUCH less.
__________________
He is your friend, your partner, your defender, your dog. You are his life, his love, his leader. He will be yours, faithful and true, to the last beat of his heart. You owe it to him to be worthy of such devotion. -- Author Unknown