Genuine OEM Mitsubishi factory replacement M18 washer for the 6-speed Evo 8/9 transmission fill plug and also the 4G63 DSM/Evo/GVR4 oil filter housing plug. STM has a few diagrams pictured for reference.

Transmission Fill Plug M18 Washer:
2003-2006 Evolution VIII IX
• Fits 6-speed MR only

4G63 Oil Filter Housing M18 Washer:
1992-2006 Evolution I-IX
1990-1999 Eclipse GST/GSX
1990-1998 Talon TSi
1990-1994 Laser RS
1991-1992 Galant VR-4
• Fits all 6-bolt and 7-bolt 4G63

Purchase Includes:
(1) M18 Washer

Diagram images are for reference and may not represent your exact model.
As always, please do additional research with your VIN to confirm part numbers.