The ball used in softball isn't as soft as the name of the sport suggests. The ball is serviced via an underhand motion and hit with a bat. The softball construction matches with the baseball to a certain degree and has minor differences only including the size. The International Softball Federation regulates all the rules designated with softball's sizing and manufacturing.

Softballs are manufactured by sewing and sticking the core and cover together. The official league matches feature softballs of size ranging from 10 inches to 12 inches, whereas 16 inches large softballs are used in some of the slow pitch city leagues.

During the fast-pitch international matches, approx. 12-inch softballs are used that weighs around 6.25 oz to 7 oz. This size is also applicable for slow pitch matches played by males of 13 and above years of age. On the other hand, the slow pitch softballs for females (18 and younger) and for kids (12 and younger) weigh between 5.87 oz to 6.125 oz and have a circumference of approximately 11 inches.

Manufacturing of Softballs

• Core - The core of the softball is made either with a mixture of polyurethane or long fibre kopok or a mixture of cork and rubber. The circumference of core varies widely depending on the league-set and its standards. 
• Cover - The exterior layering of softball is regarded as a cover. These are manufactured either from synthetic materials, leather or rubber and are white or optic yellow in colour. However, white balls are also used sometimes but yellow balls are most commonly used and allowed officially.
• Seams or Stitches - Stitches hold the parts of the cover together. Colour of the stitches varies widely depending on the softball association. Fast-pitch balls have a raised seam that offers better control and grip. The slow-pitch softballs, on the other hand, have lower-profile seams that offer maximum distance and better flight.

Types of Softballs depending on the size

• 11-inch Softball - The 11-inch balls are ideal for fast-pitch softball matches. The balls are more rigid and 2 inches bigger than a standard baseball. The fielders are required to wear gloves while handling the ball. 
• 12-inch Softball - The 12-inch softballs are a little softer than the 11-inch variant. These are a bit harder to pitch than smaller balls because of their size and softness which in turn slows down the speed of the game.
• 16-inch Softball - The 16-inch softballs are widely popular in Chicago and New York. These balls are softer than the 11 and 12-inch variants. Although, due to their bigger size, the balls can't attain a longer distance. The fielders don't require wearing gloves during the match.

Evolution of Softballs through the years

The sport of softball emerged for the first time in 1887 on Thanksgiving Day in Chicago. The first original softballs were used by the Farragut Boat Club and had a circumference of 16 inches. Later, Lewis Robert Sr. organized softball matches (known as kitten ball, lemon ball or diamond ball during those days) for firefighters in Minneapolis and used a 12-inch softball; the size which was highly popularized later. But people of Chicago believe that softball should be played with a 16-inch ball and the games using this size of the balls are referred to as cabbage ball, super slow pitch or mushball. Today, in other parts of the world, 10-12 inches balls are preferred in professional softball matches.