The TANDEM SPEED double pulley is designed for zip lines or tensioned highlines (Rope compatibility: Diameter: 13 mm or less) and has stainless steel sheaves mounted on sealed ball bearings for excellent efficiency. It accepts up to three carabiners to facilitate use.

Using the TANDEM SPEED trolley on cable

Until September 2021, the Instructions for Use for the TANDEM SPEED trolley indicated compatibility with ropes or cables up to 13 mm in diameter.

Since September 2021, trolley use on cable has been guided by the EN 17109 standard, which covers only Adventure Parks. The TANDEM SPEED does not meet two criteria of this standard: drop resistance and finger protection. There is no other PPE standard covering trolley use on cable.

For Adventure Park use on cable, the only certified Petzl trolleys are:

- The TRAC CLUB (P023AB00/P023AB01) and TRAC GUIDE (P024AB00/P024AB01) trolleys.

- The TRAC (P023AA00/P023BA00) and TRAC PLUS (P024AA00/P024BA00) trolleys.

The TANDEM SPEED Instructions for Use thus no longer indicates compatibility with cable. However this pulley has stainless steel sheaves, which still allows it to be used on cable up to 13mm in diameter, for any use except an Adventure Park environment, while respecting the information in the Instructions for Use.

https://www.petzl.com/US/en/Operators/Using-the-TANDEM-SPEED-trolley-on-cable?ProductName=TANDEM-SPEED