The Amish Outfitters planer boards pull like mules. To keep them from jumping around in the waves and to protect our mast systems from taking too much abuse, the planer board snubbers/shockers are a shock absorbers for planer boards. Heavy UV resistant tubing with 400# Spectra inside make these shockers durable and effective. 350# swivels and clip will take years of abuse. These are packed in two packs.