These .50 Caliber paintball hoppers are designed specifically for the new .50 Cal paintball guns that have hit the market in 2010. .50 Cal Paintballs are smaller than the standard .68 (inch) caliber paintballs. There are very few manufacturers that currently make .50 caliber markers. These manufacturers include Spyder .50 cal, and MilSig. 99.9% of all paintball guns DO NOT use these .50 Hoppers!