Its engineered design is the secret. Our design team starts with Allied's Gatorshield 50,000 PSI, galvanized structural steel tubing. It's made for maximum performance in greenhouse design. Gatorshield averages 42% stronger and 15% lighter than Schedule 40 pipe. Still, tubing is tubing. It's the design that makes the difference. Nothing is used that will weaken your frame and cause it to fail when you need it the most! Frames available from 12' to 30' and any length in increments of the bow spacing.