The Endurance line is the "heavy-duty" option for riders who prioritize durability and reliability in wet or dirty conditions. While down is lighter, synthetic insulation like Perefill 3D excels when moisture is a factor, as it continues to retain heat even if it gets damp from a leaky tent or heavy condensation.

Why We Like It
These bags are a bit more durable than a down sleeping bag, at the expense of packability. With a 50D polyester ripstop shell treated with PFAS-free Teflon and a massive, failproof #10 YKK zipper, the Endurance series can handle being stuffed into panniers and slept on in scrubby desert sand.
 
The bag is packed with thoughtful features: a #5 YKK anti-snag zipper that actually works, a segmented hood adjustment system to trap heat, and four pad attachment loops. The loops allow you to secure the bag to your sleeping pad, ensuring you don't slide off onto the cold ground in the middle of the night.
 
Options
20°F Option: The sweet spot for Utah motocamping for spring and autumn riding.
0°F Option: Choose this if you are a "cold sleeper" or plan on high-altitude camping during the shoulder seasons. I have seen overnight temps in the high 20s in our mountains and deserts even when daytime temps reach the 50s. 
-20°F Option: In all honesty, this is likely overkill for motorcycle travel. At -20°F, you will likely be dealing with black ice and snow-covered roads that make riding dangerous and this lofty bag doesn't pack down as tight as the other two options. This would be better suited for winter car-camping. 
 
Notes
When looking at these ratings, it is vital to understand the difference between a Survival Rating and a Comfort Rating. A survival rating means you won't die, but you won't good sleep. Peregrine lists their Comfort Rating temperatures, meaning you can actually get a restful night at these temps.