Boeing and International Lease Finance Corporation (ILFC) have finalized a firm order for 33 Renton-built, Next-Generation 737-800s worth more than $2.6 billion at list price, Boeing announced Tuesday.

The order is part of ILFC’s initiative to modernize its fleet and increase the balance in its airplane portfolio, according to Boeing.

“This 737 order will provide ILFC’s airline customers with advanced, highly competitive airplanes that deliver the best reliability, superior operating economics and increased passenger comfort,” said Marlin Dailey, vice president of Sales & Marketing for Boeing Commercial Airplanes in the press release.

Today’s operators fly 737s that are 5 percent more fuel efficient than the first Next-Generation 737s delivered in 1998 and additional improvements are on the way, according to Boeing.

ILFC’s new Next-Generation 737-800s with the all-new 737 Boeing Sky Interior, which introduces cove lighting and curving architecture that create a distinctive entryway.