Delta SkyMiles (Pre-WorldPerks Merger) - What is E booking class?

Was thinking of doing a coupon connection trade for a delta voucher within the US, Canada, Mexico, or Virgin Islands. Cert must be booked using E booking class. Is this the skymiles saver booking class, or some sort of paid fare class. What is inventory likely to be to virgin islands or mexico. I think I would be OK if it is as good as skysaver seats or better.

I believe it's a booking class created specifically for certain promotions, and has quite limited availability.

E
No
No
Coach travel, promotional / contest awards no mileage accrual, no upgrades


No Miles, No Medallion UG's, No PMU UG's, and no Mileage Upgrade

Availability often equals SkySaver availability for non-Medallion members.

Wasn't that the fare class used for the "escape" program?

IIRC, that was S class.