Hey Step, welcome to the Buzz.
You should probably be a little more specific, are you looking for someone that has one to sell you? What size you need to fit the boat you have? Recommendations on what brand and model to buy? Help us, help you.
If your trying to figure out size, measure from the center of each tube, and a stearin from of at least that width, or a few inches wider, should work out for you.
The river probably thought, “ he is such an insignificant, pitiful, little creature, with such a short time to live, I will let him go this time, and try to teach him something” - Buzz Holmstrum