The Front Guide 86715455 guides the shank’s reciprocating movement in HC25 Hydraulic Rock Drills and blocks dust from entering the drill’s internal components. Generic front guides use low-hardness materials (HRC<40) that wear rapidly—often within 500-600 hours—leading to shank misalignment. This OEM guide bushing is made from wear-resistant steel (HRC 50-55) with a polished inner surface (Ra≤0.4μm) to minimize shank friction. Its dust-proof design includes a lip seal to trap debris, and it maintains performance until mandatory replacement after 800 hours.