I just came across this (Ferd Stiegler, Mainz Leather Frog.) Year 1935. It is in great shape. Any other information about this, or does that pretty much sum it up? Looks like it never had a Retention Strap?
Yes this looks like a nice early frog, with brass rivets and no secure strap as is ok for that period. Was observed on cases for testing tool for telephones.