Image not available$250
1 retailer
CS40 Ultra Backpack
The Outdoor Vitals CS40 Ultra Backpack is a 51 L, 1.7 lb pack that fits common carry-on limits.
- Capacity
- 51 L
- Weight
- 1.7 lb · 765 g
- Laptop
- Not published
- Water
- Water-resistant
Image not availableColor not published
Review score
From 1 review, weighted by each site’s popularity
8.4/ 10
Select a site to leave it out.
Read the reviews: OutdoorGearLab review (opens in new tab) (Jun 10, 2026). Each site’s scale is converted to our 1–10 scale and averaged; more-visited sites count more (how).
What the data says
- Lighter than 82% of the 17 other packs we list in the 46–56 L range.
- Lowest in-stock price is 4% below list price this week.
Computed from the specs below. How we write summaries.
Full specs
Last verified Oct 4, 2026
Unless marked otherwise, specs are from the manufacturer’s product page (outdoorvitals.com).
| Capacity | 51 L (3,110 cu in) |
|---|---|
| Weight (manufacturer) | 1.69 lb (765 g) |
| External dimensions | 54.6 × 27.3 × 17.1 cm (21.5 × 10.8 × 6.8 in) |
| Carry-on size | Fits common carry-on limits |
| Water resistance | Water-resistant |
|---|---|
| Main fabric | Challenge UltraWeave 200 (UHMWPE / high-tenacity polyester woven blend, laminated with Challenge RUV film) |
| Opening | Roll-top |
|---|---|
| Quick-access pocket | Yes |
| External pockets | Side, Hipbelt |
| Bottle pockets | 2 |
| Hydration sleeve | Yes |
| Frame | Internal frame |
|---|---|
| Hipbelt | Padded |
| Sternum strap | Yes |
| Load lifters | Yes |
| Torso sizes | Small, Medium, Large |
| Built for | Backpacking, Hiking |
|---|---|
| Warranty | Outdoor Vitals Performance Promise |
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