There are three types of stiffeners that can be used to reinforce your panels:

Standard Stiffener: This piece of U channel metal has an opening in the middle for legs to pass into that helps keep 2 panels in a straight line. They are about 9" long and powder coated silver vein.

T-Stiffener: The T stiffener can be very useful for you. When you have a panel you want to come out from the joint of two panels (that are in a straight line), you can put a T stiffener to secure that panel that is coming out. We recommend using the T stiffener when you have this situation in your booth.

L-Stiffener: This, with the straps will help secure your corners. This product does not actually support your corners completely. If you are already using the Support Bars to support your corners then chances are that you will not need the L stiffener. The L stiffener will add support but it does not hold the panels at the exact angle, like you assume it would. The support bars are you best bet in securing angles. But it would be helpful in a situation where you just cannot use your support bars, or have just two panels together and don't want to use a support bar. The L stiffener would help in those cases.