This is a set of 3 rubber bands for muscle training and stretching. Unlike rubber tubes, they won't suddenly snap, so you can use them with confidence. The resistance levels are: Easy 11.3-18 kg, Medium 18-24.8 kg, and Heavy 24.8-36 kg. These are equivalent to VRTX bands. They roughly correspond to VRTX bands #1, #2, and #3. Using Medium and Heavy bands together provides a resistance level equivalent to VRTX band #4, and using all three bands together is equivalent to VRTX band #5. The bands are 3 cm wide and 2 meters long. They can be used for full-body training and stretching. A drawstring bag and a simple instruction manual are included. You can find usage instructions and training methods for different body parts on VRTX's YouTube videos and Instagram. The colors may vary. Please note that the functionality is the same. Since rubber is used, there may be a rubbery smell. In that case, the smell will gradually disappear with air drying or washing. Please refrain from purchasing if you are sensitive to smells.