High quality fresh factory belt made in Europe for cassette recorders: GRUNDIG C-4100 EXTRA STRONG LONG LASTING Even stronger than the original, resistant to various acids, high temperatures, UV and high mechanical resistance. The straps must be able to absorb mechanical and motor vibrations that are possible only with the best straps with a high content of natural rubber and other matching materials that guarantee good wear resistance and the right traction but without deformation. After many experiments and tests, we have achieved this winning mix. The lengths of our straps are always exactly tailored to the described model, they are not adjusted and stretched to allow them to enter by "strength" by damaging the mechanics over time and removing the strap from both the durability and the ability to absorb vibrations well. In fact, unlike many of us, we have many sizes, not a few "standard". You dont even have to worry about the mounting direction because you smooth on all sides.