Stanley Fatmax Antivibe All Steel Curved Claw Hammer One piece steel construction Oversized striking face(25% larger 'Sweet Spot') Precision balanced heads Lightweight Construction Providing faster, more accurate nailing! 100% Steel Construction Anti-Vibe technology Head weight: 570g (20oz) The Stanley Fatmax Antivibe Claw Hammer (FMHT1-51275) has a proprietary tuning Fork which is designed to reduce vibration as well as fatigue.