RD Louvred face diffusers

Louvred face removable core diffuser, models RD1; one way face pattern
RD2; two way face pattern
RD2C; two way corner face pattern
RD3; three way face pattern
RD4; four way face pattern
RD4/B1, 2, 2c, 3, and 4  way appearance with the required diffusion pattern achieved by the use of blanking quadrants in the neck of the diffuser. RD4/A two position four way core RD*L rectangular diffuser, core pattern as required.