This hardball is recommended for tournament or recreational level of doubles play.  A red dot squash ball has a medium bounce with high speed (hang time). 

Dunlop Elite Hardball Doubles Squash Balls (12 balls) Details:

• Pack Size: 12 squash balls
• Colour: Blue
• Dot(s): Single Red
• USSRA, PSA, & WSA Approved
• Product Code: P700202