These square washers from MacLean Power Systems are made of hot dipped galvanized steel and have a 1/4" thickness. They have a 4" diameter and a 1" diameter hole size. The box contains 50 washers and are part number F615195. These washers are perfect for hardware and industrial use and are measured in inches. The finish is also galvanized, ensuring durability.  For shipping purposes, they will be taken out of the factory box as they weigh one pound each.