MSE Intelligently Re-engineered™ HP Q7551X (51X) High Capacity Black Laser Toner Cartridge This premium-quality, certified cartridge from MSE® puts quality at the forefront. Going one step further than our other compatible cartridges, this product is intended for customers with strict quality requirements. All MSE cartridges are intelligently re-engineered™ with new, matched internal components. This guarantees perfect print quality and image density (darkness), faithful to the original HP specifications. This is possible because MSE cartridges are built with proprietary OPC drums, matched to the proprietary toner formulation used. MSE cartridges are a no-comprise replacement to original HP cartridges, all the performance without the high price.