Contains 4 each of 1/4", 3/8" and 1/2" packed in a fancy counter display. Display takes up just three square feet of shelf space Socket trays come in SAE and Metric sizes for 1/2", 3/8� or 1/4" drives. They're molded of rugged ABS plastic to shrug off lubricants, solvents and abuse. Display holds four trays in each of the three SAE sizes and three Metric sizes