Well you may not know if you are not shipping all the time but UPS and FedEx changed thier DIMS for shipping. Our 6x6x5 bopx used to be able to ship out at one pound. But when things changed at the begining of 2011 we knew we had to get a new box ready. So we have one ready to go for you now. Order our 6x6x4 box today for lower shipping cost when you ship. This should save you some good money over the course of a year. We have more products coming on line this week as well. Remember TSK Supply for all your shipping and reptile supply needs.