Unlike in three season tents, the inner tent in this "3+" season Alto Tr1 Plus is made of Nylon fabric, preventing wind from entering. The structure stands up against light snow loads - a great choice if you want a lightweight tent, but avoid actual snowstorms. The tent can be pitched fly first, keeping the inner tent clear of the weather. The Tension Ridge pole structure creates very nice space compared to the tent's low overall weight. The doors are also larger than those of many competing models. The word Plus in the model name refers to both the inner tent structure and the floor's higher hydrostatic head value: 2500 mm instead of 1200 mm. - Three/four season shelter - One person model - Hybrid dome structure - Two doors and vestibules - Aluminum poles: manufactured by DAC, model TH72M - Fly: 15 denier ripstop nylon, with PU and silicone treatments, with sealed seams - Inner tent: 20 denier ripstop nylon - Floor: 20 denier ripstop nylon - Three-part FairShare packing system enab