3-in-1 Multi-functional Car Emergency Life-Saving Hammer Keychain - Red + Black

Pros: - Do not take up much space. - It is very cheap and so you have a better cost x benefit. - Apparently it's quite sturdy.

Cons: - It did not come with a manual. - The whistle is very weak, if you clap, will make more noise than the whistle.

Other: - I live in Brazil and it took about 25 days to arrive. - I recommend the purchase.

Pros: it is cheap (in my country it costs more than US$ 20,00) I did not test it, but I think it will work if I need it.

Cons: I spent a long time trying to make it work, because of the steel point was stucked on the plastic cover. The spring isn't parallel to the device body. I do not know why it cost US$ 0,10 more than the green one and US$ 0,10 less than the yellow one, I will buy the green one now.

Other: I hope I do not need to use it. And if I really need, it works.