'The Mountains Are Calling' Eco Enamel Pin. Taken from the famous quote 'The mountains are calling and I must go', by John Muir. Size - 32mm x 31mm Material - Recycled Brass, metal butterfly clutch Packaging - Enamel Pin Factory branded recycled backing card.* *Alternatively, we can package your pins on your store's custom backing cards - Contact us for details. What is an Eco Enamel Pin? Eco enamel pins are our conscious response to the environmental impact of traditional enamel pin manufacturing. Recognising the harm caused by the industry—both through its production processes and the carbon emissions from importing pins via air and sea—we took matters into our own hands. Our eco-enamel pins are crafted right here in the UK, using recycled metals and VOC-free inks. They offer the look and charm of traditional enamel pins while being significantly kinder to the planet.