Finnsticks help to keep the binoculars steady especially when they are used for a prolonged time. In addition to keeping the image steady which allows for finer details of the object to be discerned, the use of the stick reduces muscle strain thus enabling longer viewing with less sore muscles afterwards. Some birdwatchers feel that the use of a finnstick does not markedly improve the viewer's ability to resolve detail, but rather improves viewing comfort and prevents premature fatigue.
As the name implies the stick was invented by the Finns but is now also used in other countries, mainly in Europe. Alternative strategies for steadying the binoculars include supporting the arms against the body.
Some birdwatchers have extended the idea by using a telescope type of stick either as a Finnstick or a monopod depending on the situation.
It's possible to craft your own Finnstick from a piece of wood (an old hockey stick used to be popular raw material). Now it's more common to use for example the leg of an old tripod as the basis for the stick. The upper end of the stick needs to be adjusted to each binocular model.
In the cold Finnish climate it's common to cover finnsticks made of metal with an insulator to keep the hands warmer.
Finnsticks are also commercially available and some binocular manufacturers provide an attachment for a finnstick (or a monopod) as an accessory.