Important! This product is activated by water. This makes it VERY sensitive to moisture contamination. Once opened this product will have a short shelf life especially if you live in a humid region. Buy and use as soon as possible. Even in the sealed container it will begin to congeal in 3-4 months.
Shrink-It is a polyurethane product that mixes with water and cures to form a soft rubber material. Once it is demolded, cured Shrink-it parts will shrink as the water content evaporates.
It may take a week or two to finish shrinking. As the water evaporates. This takes some time, although use of a food dehydrator speeds up the process.
BITY Mold Supply suggests a mix ratio of up to 3 parts of Cold Water by volume to 1 part Shrink-It.
This product has a 30 second pot life so you must be prepared to work fast. Can be demolded in 5 minutes.
If you don't get the size result that you wanted, try again, changing the mix ratio (more water for a smaller shrink, less for a bigger shrink) until you get the result that you were trying to achieve.