Dear Sir/Madam, This is marthaguan from CN. I'm looking for products with the following specifications: 1.3cm diameter ball, material can be foam rubber, sponge rubber, PU foam, etc, but not hollow. Surface must be smooth and suitable for rolling on plastic tube inner wall. Weight around 0.5g will be suitable. The ball must be uniform in size and perfectly round. Thank you for your attention. Show More