Travel icon - Patinated bronze - Russian Orthodox

This type of object is an antique Russian Orthodox cast bronze travel icon (triptych) depicting Saint Nicholas the Wonderworker.

This triptych dates from the 19th century (roughly between 1820 and 1880). These icons were cast in Russia during that period, often in workshops of the so-called Old Believers (a conservative splinter group within the Russian Orthodox Church).
Durability for travelers: This type of icon is known as a travel icon or skladan. Because hand-painted wooden icons were too fragile to take on journeys, on horseback, or during military campaigns, this sturdy cast work in bronze alloy provided a solution. Believers wore them close to the body for daily prayer and spiritual protection on the road.
Nicholas is by far the most beloved saint in Russia. He was regarded as the ultimate savior in distress and the patron saint of travelers, sailors, merchants, and the poor.
The central panel shows Nicholas in his episcopal vestments, while he blesses with his right hand and holds the Gospel in his left. The loose tab at the top displays the Mandylion (the Holy Face of Christ). The side wings show a carefully chosen selection of apostles, archangels and metropolitans (Church Fathers) of Moscow to surround the traveler with heavenly aid.
The hinges are still completely intact, and the details of the casting are clearly legible and not worn down by polishing.
This variant is entirely bronze.
On the handwritten note (the tab) is written H. Mandylion, which is the abbreviation for the Holy Mandylion.
On the bronze icon is the accompanying text in Old Church Slavonic (Cyrillic):
ОБРАЗЪ НЕРУКОТВОРНЫЙ (Obraz Nerukotvorny)
This literally means "Image not made by human hands." It directly refers to the relief image above, on which the face of Jesus Christ is depicted on a cloth (the sweat-wear/handkerchief). This type of image is known in Orthodox tradition as the Mandylion or Acheiropoieton.