This watch is part of the "Sustainable Planet" program by ZEPPELIN. The vibrant green dial is made of sustainable BioPolymer, which is produced from vegetable oil and allows enough light to pass through for the solar cell, which is invisibly mounted behind the dial and supplies the quartz movement with energy. The charge level can be checked with the push of a button. The strap is made of apple leather, which uses apple pomace from juice production mixed with binding agents to create a high-quality material.This watch is part of the "Sustainable Planet" program by ZEPPELIN. The vibrant green dial is made of sustainable BioPolymer, which is produced from vegetable oil and allows enough light to pass through for the solar cell, which is invisibly mounted behind the dial and supplies the quartz movement with energy. The charge level can be checked with the push of a button. The strap is made of apple leather, which uses apple pomace from juice production mixed with binding agents to create a high-quality material.