"Tail fins, I'll show you tail fins" is what Excelsior Rocketry has t' say about this rocket. Arrr! Blimey! Kit bashed Baby Burtha from plans by Excelsiorrocketery.com. Begad! Blimey! I listed t' price at $17.00 because it cost $7.00 for t' plans and $10.00 for a Baby Bertha kit.