(c) Hardness and Maximum Number 

The hardness of any pimple or stud is between fifty-five (55) and sixty (60) based on a shore “A” scale. The number of pimples per square inch is no less than fifteen (15) and no more than twenty-eight (28). 

No pimples or studs may be visible when the shoe is placed on a flat horizontal surface and viewed vertically. The foxing/ side wall can be contoured only in the medial forefoot and medial toe area but only within the following restrictions: the contoured area may begin in the transition area between the outsole and the sidewall but can only extend to a maximum of 1.5 cm up the sidewall as measured from the base of the outsold; and the contoured area must be smooth (not textured or undulating) but can be stepped with no more than five (5) steps, each no more than 1 mm in depth. 

Forefoot and heel areas may be separated, but there should be no more than a 2 mm step in the outsole of the shoe. 

As an alternative to the above specifications, players may use the special grass court shoes developed, tested, and approved by Wimbledon. Players desiring approval of special grass court shoes for WTA Tournaments must submit a sample shoe to the WTA at least ninety (90) days in advance of the grass court WTA Tournament at which they seek to wear such shoes. 

ii. Clay Court Shoes 

In Tournaments played on clay courts, players must wear tennis shoes generally accepted for play on clay courts or granular surfaces. The Supervisor has the authority to determine that a tennis shoe sole does not conform to such customs and standards and may prohibit its use at any WTA Tournament. 

Grass court shoes may not be worn during a match on a clay court. 

iii. Hard Court Shoes 

In Tournaments played on hard courts, players’ shoes must not cause damage to the court other than what is expected during the normal course of a match or practice. Damage to a court may be considered as physical or visible, which may include a shoe that leaves a mark beyond what is considered acceptable. The Supervisor has the 

