In 1875, Boston's Charles C. Waite became the first player to use a glove at first base, adopting the protection to save his hand needless punishment. However, the modern first baseman mitt didn't make its debut until 1941.
The difference between a baseball glove and a mitt is that mitts don't have slots for individual fingers. Catchers and first basemen are the only two positions to use mitts.
First base mitts typically have long, narrow pockets and open web trappers.
Average first base mitts measure between 12 and 13 inches long. First basemen are the only infielders permitted to have gloves that long.
A first baseman's mitt provides extra protection for the fingers, taking the sting out of hard throws. The mitts are also designed to funnel balls into the webbing for greater security. The mitt's added length helps in scooping grounders and stretching for throws.