The world's smallest gun is up for auction - and it's no bigger than the size of an average fingernail.

Le Petit Protector is an extremely rare 19th-century-style French ring gun that can be worn as jewellery - and is expected to fetch in excess of £1,500.

The tiny firearm is the first documented example of its kind to be placed on top of a ring.

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The world's smallest gun is up for auction and is no bigger than the size of an average fingernail

Sitting where a jewel would usually be, the 'petit' has a steel recoil plate that serves as the base for a pinfire cylinder filled with live 4mm rounds that could be fired straight from the hand

The tiny weapon is expected to fetch more than £1,500 at auction. It comes complete in a velvet-lined case, with 'Le Petit Protector' marked in silver on the lid

Sitting where a jewel would usually be, the 'petit' has a steel recoil plate that serves as the base for a pinfire cylinder.

The cylinder is filled with live 4mm rounds that could be fired straight from the hand.

These minuscule rounds make a loud sound when fired but generate little force - enough to penetrate one side of a tin can, according to Guns.com.

These minuscule rounds make a loud sound when fired but generate little force - enough to penetrate one side of a tin can

'Le Petit Protector' is marked in silver on the lid

Le Petit Protector sits on top of an intricately designed brass ring which is engraved with a vine design.

The ring revolver is presented in good condition and comes complete in a velvet-lined case.

On the case's exterior, 'Le Petit Protector' is marked in silver on the lid.

Alain Dilmen, Catawiki's specialist auctioneer, said: 'This rare piece is a spectacular show of craftsmanship and it is undeniably intriguing.

'Lots such as this rarely come to auction and with this gun being so unique we expect to see an influx of bids from across the globe.'

The gun is being sold through the European online auction house Catawiki.