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 peace of mind. 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 is roughly 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. You can use them 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 understand that the functionality is the same. As these bands are made of rubber, they may have 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.