Genuine Roca flush valve washer will fit the D1D (product code: AH0003600R) and D2D (product code: AH0004800R) dual flush valves
After turning the water off and draining the cistern, access the old washer by twisting the main valve body to release from the cradle. pull off the old flush seal and push on the new one, twist the main body back into the cradle and refill the cistern
Outside diameter: 66.5mm
Hole diameter: 17mm
Thickness: 2.2mm
Product code: AH0007100R