Replacements for these earlier sensors are getting difficult to find. NLA at Rimmer's. Part no. YDB100310
There are some on eBay:
https://www.ebay.co.uk/itm/204224620...Bk9SR6CgyJq_YQ
Avoid those with white oxide as they've probably been swimming.
Or post in the "Wanted" section, some people like Arctic are know for their extensive hoards
Regards