Product# E3 .48 Diamond Fire Technology.

 

The $10 gasket is generic and the $40 is Rover.

 

Atlantic British clearly marks their genuine land rover parts. I would not be surprised if the two companies are selling the exact same brand.

For example:

Aftermarket: http://www.roverparts.com/Parts/PEM100990.cfm
Green Oval: http://www.roverparts.com/Parts/PEM100990G.cfm

 

Mike, did you have good luck with the E3s?

 

Since I installed mine, I have had 4 or 5 friends install them all with the same changes, smoother idle, better low end torque and a lot less throttle pressure either in town or when driving in the mountains, I really like them along with their 5 year, 100,000 mile warranty.
My MPG is up about 1.5 over my last plugs which were only 3000 miles or so old.