The Big Agnes Anthracite 30° is a synthetic-fill bag aimed at summer and shoulder-season trips, where synthetic's resistance to moisture matters more than shaving the last grams. Its FireLine Pro Eco insulation is made from recycled fibers and holds a -1°C (30°F) rating, enough for cool nights without the performance collapse down suffers when it gets damp.
At 964 g and packing down to 23×20 cm, it sits on the lighter end of synthetic bags, though it still trails true down bags in warmth-to-weight terms. The shingled baffle layout and full-length, two-way left-side zipper let you vent easily on warmer nights, while a draft collar and draft tube along the zipper cut heat loss where it matters most.
It is designed to zip together with a compatible second bag for couples, and is sized for users up to 183 cm tall. Shell and liner are both recycled polyester with no PFC treatments, making it a reasonable pick for hikers who want a lower-maintenance, more sustainable option for summer backpacking and car camping.