Calculator Security Base w/Lock

[Ren]

Thank you Duane Hess for all that research!
I'll order a couple of the keys you mentioned.
I'll have to double check the Model Number of the cradle I have, but it is a faint emboss.

[edit] It has been over 30 years, but the other HP-35 have may have also come with a Security Cradle (given to me by a then girlfriend) It may have been the start of my "collection". But, I didn't see the significance of the cradle (it likely came with a key) and I threw it out (Sigh!)