PU stands for Polyurethane.

Polyurethane is an oil-based synthetic material. Polyurethane, mostly in the form of flexible foam, is one of the most popular materials used in home furnishings such as furniture, bedding, and carpet underlay. As a cushioning material for upholstered furniture, flexible polyurethane foam works to make furniture more durable, comfortable, and supportive. It is perfect for items that need to be durable and has many use cases from skateboard wheels, and a PU yoga mat to the comfortable feel of a mattress or sofa.

Natural rubber is made by extracting latex – the liquid sap – from certain types of trees and other plants. While most latex is sourced from the Hevea brasiliensis tree, aka the rubber tree, over 2,500 varieties of trees and plants (including dandelions) produce the right kind of sap.