What are the differences between the YardStash IV and the YardStash III?

The YardStash IV is constructed entirely of thick, heavy duty, rip proof, weatherproof and UV proof tarpaulin while the YardStash III features a tarpaulin roof and PVC lined polyester body. The material and roof design of the YardStash IV are optimized for more extreme weather conditions, superior snow shedding and increased durability. The YardStash IV is also two inches deeper than the YardStash III and is backed by a two year guarantee while the YardStash III has a one year guarantee.