"The SMO leather shells are a pure natural product made of Swiss leather. Each bowl has its own character and is made in Switzerland according to traditional craftsmanship. The SMO leather case fits well in the hand and is the ideal companion for indoors and outdoors. It doesn't need any special care and is made to last. The vegetable-tanned cowhide darkens a little over time and gets your own personal touch depending on how you handle it. The shell becomes a little softer and more supple over time, while the shell shape remains permanent."