Bosch HS2169 1 1 8 Inch Hex Shank 21 Inch Clay Spade Chisel Heavy Duty Forged Alloy Steel Mud Dirt Trenching Digging Bit For Breaker Hammers Trowel Blades Universal Bolt Configuration: Machine stamped mounting Universal Bolt Configuration: Machine stamped mounting slot arrays enable immediate cross brand compatibility across leading 36 inch trowel models Square Head Design: 5 inch square profile perfectly scrapes the sides and bottoms of buckets to ensure a uniform mix and Frozen Earth with Mechanical Speed This simple layer allows the thick mud and compressed soil blocks to slide cleanly off the shovel face rather than gumming up or straining your jack hammer mechanism