Air Chamber Type - T16Thrust @ 6.5 bar Air - 6,709 NHydraulic Cylinder Size - Ø25mmThrust @ 100 bar Oi -4,909 NAir & Hydraulic Brake Chambers convert air pressure into movement of the piston/diaphragm which links the trailer brake leaver to apply the brake;the hydraulic portion allows the use of hydraulics instead where fitted.