Arc'teryx Cerium SL vs Montbell Ex Light Down Jacket
Weight and specs compared for 2026 — and which one to choose.
1000 fill power down with synthetic insulation at shoulders for durability.
900-fill ultralight down jacket in minimal packable design.
Building a pack? Add either one to your HikeLoad list, or drop its weight into the base weight calculator, and see what it does to your total weight.
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Arc'teryx Cerium SL vs Montbell Ex Light Down Jacket: which should you buy?
If saving weight is your priority, the Montbell Ex Light Down Jacket wins — at 195 g it is 40 g (17%) lighter than the Arc'teryx Cerium SL (235 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 clothing - mid layer page, or browse the full gear weight database.