Castrol Alpha ZN 150 has been discontinued in the UK. Alpha ZN 150 gear oil had mild extreme pressure and anti-wear properties and was intended for the lubrication of worm-wheel gearboxes and spur gears where a full extreme pressure gear oil was not required. Castrol Alpha SP 150 is the suggested replacement. It is a mineral gear oil of the same viscoisty but with full extreme pressure properties - CASTROL ALPHA SP 150
