Should a TAZAPPER make a visible spark/sound? Ours doesn't.

Hi!

My partner recently bought a Tazapper, which we're both quite happy about. It's an original TAZAPPER, from the kink shop:

http://thekinkshop.com/product/tazapper/

But: our tazapper doesn't behave the way we're used to seeing them work in videos. When the button is pressed, it doesn't create a visible spark, and it doesn't make any noise. Note: this is when it's held out in the air, with no skin contact.

When it is in contact with the skin, it *does* deliver a serious shock. The shock is stronger than I expected from reading reviews. It's painful, and I tend to have a high tolerance.

So I'm wondering: Is this unit defective (and potentially very unsafe)? Should a properly working tazapper create that trademark spark and "snap!" sound you see in video scenes (link of one in action - with nudity - below):

https://www.flyflv.com/movies/11631/screaming_for_pussy_and_nipples_punishment

Please help! We don't want to get hurt.