The Therm-a-Rest Parsec 20F/-6C is a lightweight down bag rated to 0°C comfort, -7°C limit, and -24°C extreme under EN/ISO 23537, designed for three-season use. A 420 g fill of 800-fill down at a 90/10 down ratio is distributed 60/40 favoring the upper body, and horizontal box-baffle construction keeps the insulation in place. At 720 g, under the 800 g mark, the Parsec 20F counts among the lighter choices for demanding alpinists and fastpackers.
Unlike other bags in the range, this one has a single-direction zipper rather than a two-way one, so it cannot be opened fully flat as a quilt. The shell is 20D recycled nylon ripstop with a DWR finish, and the bag includes a draft collar, draft tube, and internal pocket. A stuff sack and separate storage sack are both included. The down is RDS certified and the fabric contains recycled content, though the bag is not marked PFC-free. A maximum user height of 167 cm corresponds to the short size.