Check the listing for details. Pro-Mold # PC4 1952-1956 Topps Mini-Snap Card Holder New 3 count lot. Listed at 7.85 USD. Three Pro Mold PC4 1952-1956 Topps Mini-Snap Card HolderInvented by Pro-Mold in 1991 (U.S. Patent 5,224,600), the mini-snap is a two piece snap design card holder that is ideal for inexpensive trading cards. The mini-snap was the first baseball card case to fit into the standard set storage boxes allowing you to keep complete sets in place with the most expensive cards being preserved in this holder.Strengths: Inexpensive. Small and compact which allows for storage of many in smaller spaces particularly in standard set storage boxes that hold complete sets of collectible cards from trading card manufacturers like Bowman and Topps.Weaknesses: With its two piece snap design there is always a chance that it could come apart if your drop this baseball card case on a hard floor. For real expensive baseball cards, use a one screw screwdown. Some people, like children, have a hard time opening this holder. Use a small coin like a dime to wedge it into the slot on the side of it to open if necessary. Aliases: Pre-1957 Mini-Snap Tite, PC-4 Item Name Typical Card holder is used for Inside Dimensions (Where card fits) Outside Dimensions PC4 Vintage cards from the 1950's .033 by 2.68 by 3.8 (inches) .330 by 3.143 by 4.515 (inches)