As the latest addition to the Perpetual family, the Edition version has been launched by Pirastro. This string set is the most powerful of the family and Pirastro has provided a detailed explanation (see link below). 

The A and D strings are made of steel, wound with chrome steel, the G and C strings have a multi-wire steel core, with tungsten winding. The Cadenza G & C strings were created to provide players with lower tensions to match their instruments and allow older cellos to open up and play freely. See also below chart.

Click here for the datasheet of Pirastro Perpetual cello strings.