This is the main seal / washer / o-ring for the Seeley Breezair, Braemar and Coolair electric drain valve. The washer is 34mm.

This is the seal that the piston presses against when the drain valve closes. The original seal was black in colour.

Note that there is a separate o-ring for the bottom plumbing connection (where the drain valve screws into the base of the unit). You can find that o-ring here.

You can find the Drain seal/washer in the below models:
All Breezair EXH models EXH130, EXH150, EXH170, EXH190 and EXH210.
ALl Breezair EZH models EZH175, EZH215.
All Breezair EXQ models EXQ130, EXQ150, EXQ170, EXQ190, and EXQ210.
All Breezair EZQ models EZQ155, EZQ175, EZQ215.
All Breezair EXS models EXS140, EXS160, EXS180, EXS200 and EXS220.
All Breezair EXD models EXD150, EXD170.
All Breezair EZD models EZD155, EZD175.
All Breezair EM models EM105, EM125, EM145, EM165, EM190, EM210.
All Breezair ES models ES105, ES125, ES145, ES165, ES190, ES210
All Breezair EV models EV130, EV160, EV195, EV215.
All Breezair EX models EX125, EX145, EX165, EX190, EX210.
All Breezair EZ models EZ130, EZ160, EZ195, EZ215.
All Braemar BMQ models BMQ500, BMW650, BMQ750, BMQ850, BMQ900, BMQ1150.
All Braemar LCS models LCS280, LCS380, LCS480, LCS580.
All Braemar LCQ models LCQ250, LCQ350, LCQ450, LCQ550.
All Braemar LCB models LCB250, LCB350, LCB450, LCB550.
All Braemar BM models BM500, BM750, BM900, BM1150.
All Braemar RPC models RPC200, RPC250, RPC320, RPC400, RPC450.
All Braemar RPCQ models RPCQ250, RPCQ320, RPCQ400, RPCQ450.
ALl Braemar RPCQI models RPCQI75, RPCQI150.
All Coolair CVP models CVP700, CVP950, CVP1100
ALL Coolair CPL models CPL450, CPL600, CPL700, CPL850, CPL1000, CPL1100.
All Coolair CPS models CPS450, CPS700, CPS850, CPS1100.
All Coolair CPQ models CPQ450, CPQ700, CPQ850, CPQ1100.
All Coolair LCA models LCA250, LCA350, LCA450, LCA550.
All Breezair XTR models XTR2000, XTR3000, XTR4000, XTR5000.

**Please note that for warranty and safety reasons, electrical components must only be serviced by a qualified person.