ULTRA STRONG- 1cm thickness Zinc Alloy and ABS made lock, is sturdy and durable with high grade of anti-theft, anti-breaking and anti-cutting function. UPGRADED DESIGN- The lock core surface is fully sprayed with rubber lacquer, which can ensure lock’s water resistant and anti-corrosion. The anti-impact bumper can effectively prevent damage to the bicycle frame. UNIQUE KEYS- Every 3 stainless steel keys are uniquely designed for each lock, different from combination code lock which may be opened randomly by others. Use one key and keep another two as backups. HIGHER SECURITY- Bicycles are mostly quick-release seats, there are security risky, can easily take away. Unfolding lock length can be expanded to 78cm which can lock the wheel and seat. EASY TO USE- The folding lock dimension is 6.6*5.5*7.5cm which can be stored in top tube bag, saddle bag, etc. It weighs only 575g and can be easily installed with bracket.