... tension test Tension force:custom. Item nameTennis ball with elastic string and computer stringMaterialPolyster/LatexDiameter0.45mm-0.5mm ColorBlack (we ... 100D,140D,170D,210D,420D,840D latex 52# Model No.TLX023 ManufacturerDongguan City Audelon Textile Co,Ltd BrandADL Diameter 0 ... Packing method 1 tube insert a opp,and many tube in a carton tennis ball with elastic string and computer string