The Solid Plug 86418357 seals unused process holes in HC25 Hydraulic Rock Drill housings, a critical role in protecting internal components from dust and debris. Generic solid plugs often lack proper sealing features, allowing contaminants to enter and accelerate wear. This OEM plug includes an integrated that accepts standard O-rings, creating a tight seal with the housing. It is made from wear-resistant cast iron that resists impact and deformation, ensuring a secure fit even in harsh mine conditions. Replacement is only needed if the plug becomes loose or damaged.