Spring Balancer EW3-5-9-15-22kg Self-Locking Tower-Style Pull Hoist Spring Suspension Balance Automatic Control Aluminum Alloy Housing Wear-Resistant and Durable Features a thickened aluminum alloy housing that reduces overall weight for lightweight portability while enhancing impact resistance. Aluminum Alloy Tower Effortless Control Embedded self-locking control system enables smooth vertical adjustment. Lightweight and Easy to Operate Anti-Twist Steel Cable for Enhanced Durability Reinforced thickened steel cable offers superior toughness, abrasion resistance, corrosion resistance, and fracture resistance. Alloy Steel Hook for Secure Retention Forged high-strength alloy steel hook with safety latch prevents accidental detachment.