Q-Connect HP LaserJet toner high capacity black Q7551X. Ref: LS-OB-HP86-K0. For a higher printing capacity at a lower price, your best option is this HP compatible high yield Q-Connect laser toner. Developed specifically to fit the LaserJet 5Si, MX and 5SI NX Copier 8000, this cartridge will fit your machine perfectly and is guaranteed to deliver time and time again. Give it a try and you won't be disappointed with the results. Page after page of clean, well-defined print at a fraction of the price you'd expect to pay.