... rubber sponge ball for pipe cleaning:Concrete Pump Cleaning Ball size from 1''-8'', soft, medium, and hard available ... ,medium softOD95mmDN100 (4 inch) soft ,hard ,medium softOD124mm DN125(5 inch) soft ,hard ,medium softOD150mm DN150(6 inch) soft ... types upon requestMaterialnatural rubberapplacationcleaning the pipeline of concrete pump and concrete pump truck in construction work equipment PM DN125 ...