Martin, there may be 2 formulations of rubber on the shelf, "E" or "non-E", but I've never seen that, what I've experienced is that 20, 30, 40 year old rubber parts [even NOS] don't stand up to use as long as current production - and the thing that's the most 'harmful' to rubber is ozone
the fact that older formulations of rubber don't stand up as well doesn't mean the E is 'harmful' - I've found modern formulations of rubber work better and last longer in all applications, like wiper blades and tires and brake hoses
Bill
