Grandstream HT801 Single Port ATA.

Used for a couple of years, but no longer required as we stopped using our old analog phone with landline. 
Comes with power supply.

Specs: https://www.grandstream.com/products/gateways-and-atas/analog-telephone-adaptors/product/ht801

$30 incl postage (extra for RD)

Also have a set of Panasonic KX-TG handsets that I used with this ATA adapter, if anyone wants them.