Stage lighting pros, these M9LZY truss clamps are exactly what you need for securing your moving head lights! The 4-pack gives you plenty for multiple fixtures, and each clamp boasts an impressive 220-pound load capacity. With 12mm mounting holes and 4.13-inch pin spacing, these work with most standard lighting truss systems. The quick-lock mechanism makes setup and teardown super fast - no tools needed for most installations. Made from electrophoretic paint black steel with iron fast-lock plates, these clamps feel substantial and professional-grade. The 5.19-inch total length provides good stability, and the construction can handle the rigors of regular touring or permanent installations. Whether you're setting up for concerts, theater productions, church events, or DJ gigs, having reliable clamps is crucial for safety and proper light positioning. The black finish looks professional and doesn't reflect light, while the quick-release design saves valuable time during load-in and load-out. Much better than cheap clamps that slip or don't hold securely. Your expensive moving head lights will stay exactly where you position them, even during energetic events. If you work with stage lighting regularly, having quality clamps like these is non-negotiable for both safety and performance. Definitely a solid investment for any lighting technician or production company.