According to Deering Banjos, the New Zealand Charity Banjo is "entirely one-of-a-kind, crafted with a deep black neck bearing the shape of the New Zealand Islands on the peghead.
"With pearloid inlays of red set into the Midnight Maple fingerboard, and true blue resonator this banjo bears the country colors of New Zealand.
The drum head of the banjo is personally signed by Mumford & Sons with a personal message from the band."
The website continues: "The Charity this auction will benefit is Variety, the Children's Charity NZ who work to give disadvantaged Kiwi kids the childhood they deserve. They provide children in need with basic essentials such as warm bedding, school uniforms, shoes and stationery.
"They help provide for additional special needs such as medical and mobility equipment; as well as access to extra-curricular opportunities such as music lessons, school camp and sport. They strive to give disadvantaged children the same opportunities as other kids. Their mission is to give them a happier healthier childhood, and a foundation for a better future."