Please see very small British One penny coin for size comparison. That said, this a miniature extremely well made fob watch cap gun, I believe it was made in Austria but could be mistaken. The item "Vintage Miniature-Mechanical working Cap Gun Pistol Watch chain fob item" is in sale since Thursday, March 08, 2018. This item is in the category "Toys & Games\Vintage & Classic Toys\Other Vintage & Classic Toys".
The seller is "moonshine818" and is located in barry, Cardiff. This item can be shipped to United Kingdom, Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Australia, United States, Russian federation, Canada, Brazil, Japan, New Zealand, China, Israel, Hong Kong, Norway, Indonesia, Malaysia, Mexico, Singapore, South Korea, Switzerland, Taiwan, Thailand, Chile.