Product name: 

Compensation Devices - Tensorex C+

Description: 

TENSOREX® C+ is an innovative spring tensioning device that gives a constant pull force to the Railways and Tramways overhead contact lines (OCL), by compensating its elongation or contraction, due to temperature variations along day and night, summer and winter.

Web: 

https://www.mosdorfer.com/en/produkte/railway/