Along the last decades there has been a lot and lots of inventions that changed the face of humanity . None of the m achieved the great impact that no one can argue about its effect. in my opinion, i like the most the television. This invention changed how fast we can know the news . it entered every house and every office. It has spread the communication system, and the knowledge between different people from different countries all over the world . The next to it i think is the radio, it is being inferior to the t.v. because it has no picture, it only gives us a sound that we imagine the rest of the details .

Dog collars are greatly helpful for teaching obedience to the dogs. The dog collars will be usually a piece of chain that consists of rings at their both ends. Different types of dog collars are available in the market such as prong or pinch collars, martingale collars, E-Collars, No-bark collars etc., Prong or pinch collars will be having opened and blunt ended tips which can be pulled to pinch the neck of the dogs. This action will be producing slight pain and inconvenience. Martingale collars are helpful for preventing the slippage of dogs. These types of collars are usually made of leather, cloth or chains.