NEW YORK — Apple's long-awaited entry into the foldable smartphone market arrives Friday, setting up a head-to-head battle with Samsung, which has dominated the category for years.

The iPhone Duo, Apple's first folding phone, starts at $1,999 and has already sold out through the holiday season on Apple's website. Samsung's Galaxy Z Fold 8, launched this summer, starts at $1,899.99 and is the company's lightest book-style foldable to date.

On paper, the two devices are remarkably similar. Both open like a book to reveal a 7.6-inch inner display, both use a wider "passport-style" shape and both target buyers willing to pay a premium for a phone that doubles as a small tablet. But they differ in important ways, from weight and durability to cameras, software and price.

Here is how the two phones compare, along with the main pros and cons of each.

Price and availability

The iPhone Duo starts at $1,999 for 256 gigabytes of storage, rising to $3,199 for 2 terabytes. Across the storage tiers both phones offer, the Duo costs $100 more than the Galaxy Z Fold 8, according to comparisons by Technology.org.

The Galaxy Z Fold 8 starts at $1,899.99 and tops out at 1 terabyte of storage.

Availability may be the biggest practical difference right now. Samsung's phone has been on sale since August and is widely available. The iPhone Duo, by contrast, sold out within minutes when preorders opened Oct. 16. Within about 30 minutes, all configurations on Apple's U.S. online store showed estimated shipping dates of Jan. 25, 2027.

Apple described demand as "nothing short of extraordinary" in a statement to the Financial Times. Some Apple retail employees have also been told to warn customers that there will likely be no stock available for walk-in purchases on launch day, according to MacRumors.

Advantage: Galaxy Z Fold 8, for price and immediate availability.

Weight is one of the clearest differences between the two phones.

The iPhone Duo weighs 254 grams, or about 8.96 ounces, making it the heaviest iPhone Apple has ever sold. The Galaxy Z Fold 8 weighs 201 grams, or about 7.09 ounces, which makes it the lightest Z Fold Samsung has produced. That 53-gram difference is noticeable in a pocket or during extended one-handed use.

The Samsung phone is also thinner. When folded, the Duo measures 11.3 millimeters thick, compared with 9.7 millimeters for the Fold 8. Unfolded, the Duo is 5.2 millimeters thick, while the Fold 8 is 4.5 millimeters.

Apple has built the Duo with a grade 5 titanium frame and a precision-engineered hinge. It comes in two colors, star white and night sky. Samsung offers the Fold 8 in white, gray, green and purple.

Both phones include fingerprint scanners built into their power buttons.

Advantage: Galaxy Z........

© International Business Times