I recently tried Artengo squash balls at the same time as I was testing the new Artengo squash rackets.
From the product description:
Our product has been tested in our TechCenters with our technical partners and particularly with Camille SERME, ranked #3 in the PSA World Rankings. The ARTENGO SB990 ball was designed for the most demanding squash players. The ARTENGO SB990 ball was compared to the best products on the market during testing.