In such a fast developed world, we are benefiting from the convenience brought by science and technology. Obviously, many people get surprised each time when facing to a new creation and this feeling may fade away when the creation or invention becomes gradually popular or widely used. With this in mind, what inventions have ever left deep impression to you and have helped us a lot?

In my opinion, pen drive tops the list of mine. To be frank, I cannot be without it every day in my work or at home. It offers me a large capacity to keep important or confidential information and data. On the other hand, I can exchange what in my pen drive with different users with the help of USB 2.0. People who are conscious of the risks of transferring viruses via a floppy, CD, or DVD don’t think twice about plugging in a flash drive and transferring files to or from home. Perhaps the best solution to this problem is education. Flash drives are banned in some government agencies and companies, though the effectiveness of that policy is questionable. Anyway, this little tool has become part of our daily life nowadays, noted for its portable design and various shapes.

speakers enable users to enjoy music or broadcast in a large space, such as in classroom, hall or in a spacious square. We may add a computer speaker at home to listen to the music or enjoy a wonderful movie. Some speakers have two cones, one small cone to reproduce the higher frequencies, called a tweeter, and the other one cone for low and mid-range sounds. This physical split of the high frequencies from the mid and low makes a noticeable difference to the quality of the sound, which helps produce a fuller sound and clarifies the high frequency sounds, especially when reproducing orchestras or other range-demanding music styles. In fact, there are speakers with three cone configurations which comprise of a woofer, a midrange cone and a tweeter, which further enhances the sound. In addition, another feature which helps extenuate the bass reproduction is a bass-port, this is basically a hole in the speaker's enclosure usually at the back, which allows the sound pressure created by the movement of the speaker cone to escape. This creates a smooth bass sound in the same way as a subwoofer.

A waterproof flashlight helps a lot when going camping or having adventures, which usually comes with a battery and a charger. If you happen to be in the market for such a waterproof flashlight, you should ensure that you purchase one that will accomplish the tasks you desire. Actually, one never knows how functional a waterproof flashlight is until he has a try. Many people buy one in car or at home in case of emergencies. Waterproof flashlights are necessary because it's a part of the endurance kit equipment for both outdoor journey enthusiasts and indoor housewives. So I strong recommend a waterproof flashlight as it is used in more circumstances than ordinary one.