Replacement Trip Spring is found on the back of your plow's blade and used on all SnowDogg plows. both Gen 1 and Gen 2. Most SnowDogg plows will require at least 4 of these springs which run the length of your plow's moldboard frame. These trip springs are what allow your plow to easily maneuver through any hidden obstacles without damaging your plow or truck due to excessive force.