They cram a lot inside these watches.
Samsung's are notably larger than their predecessors, but that means they hold improved specs, larger displays and perhaps most importantly a bigger battery. Though the specs aren't groundbreaking, the fact that they all fit in a smartwatch size is pretty impressive, and the Gear S3 Frontier and Classic make it look good as well. Here's the full spec list:
Category Gear S3 Frontier and Classic
Screen size 1.3-inch circular AMOLED
360x360 resolution, 278 ppi
Corning Gorilla Glass SR+
Processor Dual-core 1GHz Samsung Exynos
RAM 768MB
Storage 4GB
Operating system Tizen Wearable OS 2.3.2
Battery 380 mAh
Connectivity Bluetooth, Wi-Fi, GPS, NFC, MST
LTE optional (Frontier)
Resistance IP68
MIL-STD 810G (Frontier)
Case size 46 mm
Band size 22 mm
Dimensions 46 x 49 x 12.9 mm, 62 g (Frontier)
46 x 49 x 12.9 mm, 57 g (Classic)