the black Kong toys are stronger than the red ones (they are recommended for strong chewers such as staffies and mastiffs), they aren't totally indestructible but certainly last longer.
+1 . Max has all black kong stuff, I bought an 'indestructible' tug toy he just chewed up the rope in minutes.
The good boy bone lasts about 6 months of chewing, playing fetch and tug-of-war with, it's his favourite. His kongs are nearly a year old now and showing no sign of wear at all. I put biscuit treats in them slightly larger than the hole which keeps him busy for while.
The Kong tennis balls last about a day
and their solid rubber ball is a bit heavy for play inside but started to look like a golf ball with all the tooth marks in about a week.
If you haven't seem them it might be worth looking at stag bars, Max would chew on his for so long his gums would bleed.