"Uniquely designed with scissor-action technology, the Tow Tuff Tandem Wheel Chock Pair prevent the rolling and rocking of your tandem wheel trailers and campers. Use the simple 1-step lever action to extend the wheel chocks from 1.5"" to 5.5"" for stable placement. They even prevent movement when unhooking your trailer/camper. Corrosion-resistant zinc finish inhibits rust and ensures maximum durability. The anti-theft design has a padlock hole that fits a 5/16"" or smaller padlock shank. Mfrs. 1-year limited warranty on parts. Ideal for tandem wheel trailers and campers Prevent the rolling and rocking Simple 1-step lever action Extend from 1.5"" to 5.5"" for stable placement Corrosion-resistant zinc finish Anti-theft design with padlock hole"