The upper features side ventilation holes for breathability and drainage for water and debris. The entire clog is constructed from Bio Lite which is eco-friendlier than many other injection molded foams in the market. Bio Lite has been granted a Green Leaf certificate by Intertek, an accredited independent 3rd party testing facility, verifying that this product will properly biodegrade in bioreactor landfills. Landfill biodegradation validated utilizing the ASTM D5511-18 test method, ISO 15985. The Muckster Lite offers a lighter footprint for your feet and the planet.