STRAUB couplings and parts thereof showing production or material defects, will be replaced free of charge or credited to the Customer within a period of 5 (five) years from date of delivery. Any parts giving rise to such complaints for the said reasons within the guarantee period shall be returned to our works in CH-7323 Wangs, Switzerland for inspection. Defective couplings or parts thereof can be replaced only after the results of tests conducted by our inspection department become available. These results shall be final and incontestable. The guarantee shall not cover couplings installed without due regard for our fitting instructions. This shall apply notwithstanding any contrary purchase conditions stipulated by the Customer.