Whats the name of this exhaust gasket - see photo

[donaldthomps]

Hi, can anyone tell me the name of the gasket I need where the arrow is pointing to please?

http://1drv.ms/1j00JOr

I know it's leaking, when the LPG was adjusted a whole lot of white smoke came out of the exhaust and where the arrow was pointing..

Thanks

[wonkanoby]

http://www.ebay.co.uk/itm/Reinforced-2- ... 120wt_1069