The ESI  -BOOKHINGE Adjustable Book-Hinge Truss Connection from the most trusted staging support systems in the industry, and is built to the highest standards of safety and performance. It‘s a rugged yet lightweight trussing solution perfect for mobile DJs, bands, outdoor performances, nightclubs, live mobile productions, or permanent installations. It adjusts from 0° to 180° and fits ESI 12" SQ F34 Conical trussing. Manufactured from high-grade and lightweight aluminum which is easy for transportation and setup. This product can provide a universal solution for truss angles. The ESI  -BOOKHINGE is the first trussing hinge from ESI that adjusts from 0° to 180° for unique truss construction projects. There is a built-in adjustable arm to lock the desired angle between sections of truss for unique builds. The superior construction quality of ESI trussing products guarantees many years of trouble-free use. At the heart of the system is square truss that utilizes a standard conical connector system, which easily mates with other brands of trussing of the same size and connector style, and is available in a variety of lengths to suit your designs. It also works with different types of corners, base plates, connectors and accessories that add stability while expanding on limitless configurations. ESI  -BOOKHINGE Book-Hinge Connection Features: Manufactured in ESI‘s Own Factory. Allows angles not possible with standard trussing corners Adjustable lock arm Conical couplers included Material: 10mm EN-AWT6 6061 Aluminum TUV Certified Aluminum Welding