Broke my St. Croix

I snapped the the tip on my St. Croix fishing rod and I need to ship it to them to get it repaired. Where do I get the shipping tubes from?

Post office has triangle tubes but I think the longest is 84 inches. So if your rod is a one piece and longer than 7 feet this isn't going to work. The smaller the tube the cheaper the tubes (regular or triangle) are at UPS, FedEx, or USPS.

Twin Lakes, Wisconsin. Thanks for the offer.