Here is how these two sleeping bags compare on the numbers. The Flicker UL 20 leans on low weight while the Spark 15F answers with warmth, so the pick comes down to which you value.
| Feathered Friends Flicker UL 20 | Sea to Summit Spark 15F | |
|---|---|---|
| GearScore | 87✓ | 67 |
| Comfort rating | 30 °F | 29 °F✓ |
| Weight | 25.5 oz✓ | 25.7 oz |
| Warmth-to-weight | 5.5 /100g | 5.6 /100g✓ |
| Packed size | 8.0 L | n/s |
| Fill power | 950 FP✓ | 850 FP |
| Price | $559 | $549✓ |
| Fill | Down | Down |
| Style | Quilt | Bag |
| Shape | Quilt | Mummy |
Highlighted cells mark the better spec: Flicker UL 20 in blue, Spark 15F in amber. A blank spec is never counted as a win. A lower comfort rating in °F means a warmer bag, so the warmer bag takes that row. GearScore is the overall rating (0 to 100); re-weight it on the full bag comparison. Prices are current MSRP.
The Feathered Friends Flicker UL 20 against the Sea to Summit Spark 15F is a study in priorities. The Flicker UL 20 wins on low weight and fill power, and the Spark 15F pushes back on warmth and warmth-to-weight.
The Flicker UL 20 is 1 oz lighter and higher fill power (950 vs 850). The Spark 15F is warmer (rated 29°F vs 30°F), stronger on warmth-to-weight, and $10 cheaper. On the default GearScore the Flicker UL 20 leads 87 to 67.
Pick the Flicker UL 20 if you care most about low weight and fill power, which makes it the better call for counting grams on long miles. Pick the Spark 15F if warmth and warmth-to-weight matter more to you, or you are focused on colder nights and shoulder-season trips.
The Feathered Friends Flicker UL 20. It is 1 oz lighter than the Spark 15F.
The Sea to Summit Spark 15F. It is warmer (rated 29°F vs 30°F) than the Flicker UL 20.
The Feathered Friends Flicker UL 20, 87 to 67 on the default algorithm. You can re-weight the factors to match your trip.
It depends on your priorities. Go with the Flicker UL 20 for low weight, or the Spark 15F for warmth. The spec table above shows exactly where each wins.