Overview & Obtaining
Dusters are currently one of two available hot-weather garments available in the game, the other being the cowboy hat. As parkas are necessary to survive in very cold biomes, dusters are necessary to survive in very hot biomes (e.g. Arid Shrubland, Tropical Rainforest, Desert, etc.), and recommended for temperate biomes (i.e. Temperate Forest), as both are suspect to heat waves and the former can handily reach around - or even exceed - 60 °C (140 °F) at the peak of summer. Dusters can be purchased from traders, crafted, or stripped from Outlanders and Pirates.
As a complicated garment, dusters require complex clothing to be researched and can only be made at a hand-tailoring bench or an electric tailoring bench. A duster requires 80 of any textile, and 367 seconds of work (22,000 ticks) to be created, assuming baseline global work speed and no enhancements or hindrances to sight or manipulation.
Conclusion and Comparison
Dusters are overall superior to jackets in the respect that dusters have the same base cold insulation, but cover more body parts (torso, shoulders, arms and legs), and also offer blunt protection - at the slight cost of sharp protection (7% vs 8%). A duster made out of any wool provides cold insulation on par with that of a standard parka, along with heat insulation.