Slow Pitch Softball – Women and Men Hit Different Balls

Slow pitch softball tend to be larger and softer to the touch than fast pitch softballs. Slow pitch softballs also have raised seams to help the pitcher get better control at slower speeds. While the balls for both sports tend to be covered in either leather or synthetic leather, the interiors are different. Soft pitch softballs have higher Coefficient of Restitution (COR) and lower compression to made them bouncier and softer, respectively.

Rule 2.3.3
OFFICIAL SOFTBALL
a) Only an official softball that meets the standards of the WBSC Equipment Standards Commission and is stamped with the WBSC or ISF Equipment Standards Commission adopted and approved marking must be used in a WBSC Competition. See Appendix 3 (Approved Ball Standards).
b) In Co-ed play, male batters will be pitched to with the 12” ball and female batters with the 11” ball.
EFFECTS

APPENDIX 3:
BALL STANDARDS

A. AN OFFICIAL SOFTBALL
An official softball:

1. must be a regular, smooth-seamed, concealed stitched or flat surfaced ball.
2. must have a center core made of either No. 1 quality long fibre kapok, a mixture of cork and rubber, a polyurethane mixture, or other materials approved by the WBSC Equipment Standards Commission.
3. may be hand or machine wound with a fine quality twisted yarn and covered with latex or rubber cement.
4. must have a cover cemented to the ball by application of cement to the underside of the cover and sewn with waxed thread of cotton or linen, or a molded cover bonded to the core or molded integrally with the core, and have authentic facsimile of stitching, as approved by the WBSC Equipment Standards Commission.
5. shall have a cover of the finest quality No. 1 chrome tanned horsehide or cowhide, made of synthetic material, or made of other materials approved by the WBSC Equipment Standards Commission

B. DIMENSIONS AND SPECIFICATIONS

1. The completed 30.5cm. (12 in.) ball shall be between 30.2cm. (11 7/8 in.) and 30.8cm. (12 1/8 in.) in circumference, and shall weigh between 178.0g. (6 1/4 ounces) and 198.4g. (7 ounces). The flat seam style shall have not less than 88 stitches in each cover, sewn by the two-needle method.
2. The completed 27.9cm. (11 in.) ball shall be between 27.6cm. (10 7/8 in.) and 28.3cm. (11 1/8 in.) in circumference and shall weigh between 166.5g. (5 7/8 ounces) and 173.6g. (6 1/8 ounces). The flat seam style shall have not less than 80 stitches in each cover, sewn by the two-needle method.
3. The completed ball shall have a coefficient of restitution as shall be determined and set by the WBSC Equipment Standards Commission
4. The completed ball shall have a compression standard as shall be determined and set by the WBSC Equipment Standards Commission. The load force required to compress the ball 0.64cm. (0.25 in.) must not exceed such standard when such balls are measured in accordance with the ASTM test method for measuring compression-displacement of softballs, which is endorsed by the WBSC Equipment Standards Commission.
5. Balls shall be used in WBSC championship play as follows:
   a) Adult Women, Female batters in Adult Co-ed and Girls:
   The red-stitch 27.9cm. (11 in.) ball with a COR of .47 or less with 375 pounds compression. It must have a GWSP-47 marking in addition to the WBSC or ISF logo.
   OR:
   The 27.9cm. (11 in.) ball with COR .52 with 300 pounds compression.
   b) Junior Men’s Slow Pitch:
   The white cover, white or red stitch or yellow optic cover, red-stitch 30.5cm. (12 in.) ball with a COR of .47 or less. The balls shall have a WBSC or ISF logo marking.
   c) Adult Men and Male batters in adult Co-ed:
   The red-stitch 30.5cm. (12 in.) ball with a COR of .47 or less with 375 pounds compression and a marking of MSP-47, in addition to the WBSC logo.
   OR:
   The 30.5cm. (12 in.) ball with COR .52 with 300 pounds compression.

Listed below are the standards established for each ball:

References:
https://www.wbsc.org/en/disciplines/softball
https://static.wbsc.org/assets/cms/documents/5e85a934-d622-2bd8-62f9-854264607589.pdf