Up for sale is a spares kit that is manufactured by Biffi Products. Item appears to be new and in original packaging, but box it comes in is mangled.
19-1-3

Exported By ExportYourStore

• Brand:Biffi Products, Country/Region Of Manufacture:Unknown, Cover Gasket Depth:10"
• Manufacturer Part Number:G0229A009C00, Includes:Cover gasket, vent valve, O-rings, Vent Valve Width:3/4"
• Warranty:No Warranty, Cover Gasket Length:13", O-Ring Diameter:5"

Brand:Biffi Products, Country/Region Of Manufacture:Unknown, Cover Gasket Depth:10"Unbranded