1. Solvent Delivery Quaternary Module(1) Hydraulic system; Two dual piston in series pumps with proprietary servo-controlled variable stroke drive, floating plungers and active inlet valve(2) settable flow range; Set-points 0.001 - 10ml/min, in 0.001ml/min increments(3) Flow precision; <0.07% RSD whatever is greater, based on retention timeat constant room temperature(4) Flow accuracy; ±1% or 10ul/min whatever is greater(5) Pressure; Operating range 0 - 400 bar (0 - 5880 psi) up to 5ml/min(6) Pressure pulsation; <2% amplitude (typically < 1%), at 1ml/min isopropanol, at all pressure >1 MPa (> 10 bar, > 147 psi)