What size do I need for imperial pipework?

Class O nitrile rubber pipe insulation is a flexible, closed cell, elastomeric insulation that offers reliable protection against condensation and is dust free, fibre free and CFC free with an ODP of zero. Its inherent attributes and combination of properties makes it a highly efficient method of insulating warm and cold water services, chilled water lines and refrigerated pipework for condensation control. 

NOT UV RESISTANT, CAN DEGRADE IN SUNLIGHT OVER TIME

Sold in 2 metre lengths