I bought this to cover the crew cab of a 2009 F150 with a 5.5 foot wide bed. I bought the 5.5 case and it fits like a glove with no issues. The bed has a flat fiberglass trunk lid and it had no problem sliding over the mirrors or the duvet. I will continue after some use but at first glance it seems very nice and well made. I also like the center strap to secure the center bottom to keep it comfortable in high winds. Update: Unfortunately the case is not 100% rainproof as stated in the description. It rained twice, once heavily, once lightly, and both times there was water under the canopy. I think it's still a good foil for anything but rainproof by my definition. The good news is that it is breathable and therefore dries without causing damage from water retention and condensation. I felt the need to update my rating based on the seller's description.