This functions as a portable shrine. This can be worn for protection. The piece also looks lovely hanging on a wall or mirror in a shrine you create. The object inside the window is very old and can be removed by taking the cloth off. There is glass covering the window. All seems very well made however old and fragile.
This next description is one that I looked up, giving you more information.

Inside the window is typically a small deity statue, relic or sacred mantra. The exterior is often made of silver, gold, brass or copper and is embossed with symbols such as the eight auspicious symbols of Buddhism. It is believed to bring good fortune, long life, and protection from harm to travelers and pilgrims.

I purchased this 10 years ago at a vintage religious sale. I found it to be so interesting and loved the combination of materials and meanings. I have always had it hanging in a shrine space in my studio.

Measurements length of strap to bottom 21”
Actual shrine 4.5” by 4” and is 2” deep