Six Moon Designs Swift X vs ULA Circuit

Weight and specs compared for 2026 — and which one to choose.

ULA Circuit is the lighter option — 85 g lighter than the Six Moon Designs Swift X (11% less weight). If grams matter to you, that is the one to beat.

Spec	Six Moon Designs Swift X	ULA Circuit
Weight	765 g · 0.765 kg · 1.69 lb	680 g · 0.680 kg · 1.50 lb
Brand	Six Moon Designs	ULA
Category	Backpack	Backpack

Six Moon Designs Swift X

765 g

Highly configurable 50L ultralight pack with removable stay, hip belt and vest harness options to dial in fit and weight.

Check price Full details →

ULA Circuit

680 g

Ultralight 68L frameless pack. Thru-hiker favourite.

Full details →

Six Moon Designs Swift X vs ULA Circuit: which should you buy?

If saving weight is your priority, the ULA Circuit wins — at 680 g it is 85 g (11%) lighter than the Six Moon Designs Swift X (765 g). That said, the heavier option may justify the extra grams with more capacity, durability or comfort, so weigh the trade-off against how you'll use it.

See where both rank against everything else in this category on the lightest backpack page, or browse the full gear weight database.

More backpack comparisons

Six Moon Designs Swift X vs Salomon ADV Skin 12 Six Moon Designs Swift X vs Zpacks Nero Classic Ultra Backpack Six Moon Designs Swift X vs Zpacks Nero Classic 50L Six Moon Designs Swift X vs Zpacks Nero Classic Backpack Six Moon Designs Swift X vs Zpacks Nero Classic 40L Six Moon Designs Swift X vs Zpacks Nero Classic 30L