An apple press is used to crush apples that produces an unfiltered juice that is referred to as cider. Whole apples are ground up by a hand propelled grinder.
From there the apple pieces (stems, cores and all) are put into a cheesecloth (porous) bag and transferred into a wooden cylinder.
Once in the cylinder the bag gets squeezed by a piston and the juice is forced from the solids.
Often this process requires a few friends with a lot of tenacity. Watch for wasps!
Some food safety facts to consider when using the press: here.