Here is a Hewlett Packard Comparator Plug-in 560A-58 unit for your needs.  There is nothing I can comment about this comparator except that it is well made and appears in very good shape.  It looks to require either 12AU7 or 12AX7 vacuum tubes / valves to operate.

Shipping is USPS First Class Mail that includes tracking; Priority Mail available in U.S.A. if you need your item quickly.  International sales ship via USPS First Class International Mail/Package.  International buyers wishing tracking and insurance must purchase USPS Priority Mail International.  Package weighs thirteen (13) ounces.

Combined shipping always welcome.