Wilson US Open Extra Duty Tennis Balls by Amazon.co.uk

• Tennis balls for all hard surfaces, one size, official US Open balls, ITF- and USTA-certified

• Optimum durability and performance, ideal for hard courts

• Durable, hard core, made of quality wool and durable felt, cover made of high-quality extra duty felt

• With resealable can for tidier storing and longer durability

• Contents: Wilson Tennis Balls, US Open XD, Amount: Can with 4 Balls, Colour: Yellow, WRT116201