Fuel Pump DME Relay!

I've been looking on ebay and want to buy a fuel pump DME Relay for my '83 944 for preventive reasons but there are 2 for the 83' ,

a 127 790 DME relay

and a 937 500 DME / Fuel Pump 83-85/1 Position G5 85/2-89

whats is the difference? does anyone know??

http://cgi.ebay.ca/Porsche-911-964-993-924-944-968-Fuel-Pump-Relay-New-DME_W0QQitemZ250101980070QQihZ015QQcategoryZ6763QQ ssPageNameZWDVWQQrdZ1QQcmdZViewItem

I think my cars different so I couldnt tell you. But I would just call your local Porsche dealer and ask.