Add to Cart Quick view Polypipe Polyplumb Underfloor 4 Zone Slave Unit PB4ZS Polypipe RRP (inc VAT): Price (inc VAT): Now (inc VAT): £69.99 Was (inc VAT): This Polypipe Slave unit plugs in to the Single Zone Master Unit PB1ZM and provides simple wiring of actuators & room thermostats for multiple zone control. Neon indicators show room activation...