The meramac zf series tents are all free standing 2-pole designs with shock corded fiberglass. The ferrules are the “connectors” that hold the poles together and we use aluminum, rather than steel, because aluminum can never rust. Our fiberglass poles are also normally one size larger than normal to offer you a Sturdier, stronger tent. We use lightweight but strong polyester fabrics. The walls are uncoated so the tent can “breathe” under the urethane coated fly. The fly uses a pole in the top, which gives you an awning over each door for excellent rain protection. Our fly is full length on the sides, not 3/4 length like some others, for better weather protection. We even have our factory seal the seams on the floor and fly for maximum water Repellency. Entry and exit are enhanced with 2 doors, which means if you have to get out at night, you don’t need to crawl over the others to get to the only door. The second door is also nice for extra ventilation in hot, muggy weather. Our door zippers are a #10, which is one size larger than most, for extra durability. Mesh storage pockets and a gear loft are included to help you keep your gear organized. Zf series: which stands for bigger zipper and heavier floor. The zipper for a zf 5621018ZF is upgraded from a #8 to a #10. The floor used in the zf models is a 4 oz. Nylon oxford, which is almost twice as heavy as normal nylon taffeta floors. Zf models do not have windows on fly.