Which famous invention was significantly redesigned after customers complained that its original form was causing severe burns to users?

Throughout history, some of the world's most successful inventions were dramatically improved or completely reimagined based on customer feedback. This poll tests your knowledge about pivotal moments when consumer insights directly influenced major innovations, creating the iconic products we know today. Can you identify which customer-driven modification truly transformed an invention's trajectory?

This is a live public trivia poll on AIPolls.Net. Vote and see real-time results.

The microwave oven, which originally lacked a protective shield and proper insulation
The Gillette safety razor, which initially had a single-edge blade that frequently cut users
The pop-up toaster, which was redesigned after the original model had exposed heating elements
The electric iron, which first reached temperatures too hot to handle safely