There are variations in profile design other than circular. These include O – rings x – shaped profiles, commonly called x – rings or quad rings. When squeezed upon installation, they seal with 4 contact surfaces – 2 small contact surfaces on the top and bottom.
This contrasts with the O – rings comparatively larger than single contact surfaces top and bottom. X – Rings are currently being marketed as being more durable than O – rings. Mostly these quad rings are used to seal hydraulic, pneumatic and wherever sealing is required.
The parting line construction is separated from the sealing line and even in quad rings / x-rings the improper flash removal will not have impact on sealing performance.