Tremolo block (inertia block) for Stratocaster. Made of steel and heavy, so it can be expected to improve sustain. Metric standard, with 3 screws. It was attached to a guitar, so there are scratches, but there are no stripped holes, so you can use it without any problems. Hole spacing: 10.8mm Screw spacing: approx. 22mm For 5mm arm Weight: 288.5g (excluding screws)