Ok, I'm confused now!

[Gray Wolf]

On the left, in gold I see a Fat Handle Tech, and a Ball End Tech.
On the right, in silver, I see the same handles, but what are these razors with TEETH?

 

[amishmotorboat]

Those are old type heads with tech handles. The old handles likely cracked as they were prone to do, and the owner replaced them with the sturdier and more plentiful tech handles.

 

[michiganlover]

Those are old type heads with tech handles. The old handles likely cracked as they were prone to do, and the owner replaced them with the sturdier and more plentiful tech handles.

+1

While not the actual configuration from the factory, this configuration seems to be quite common. As nearly all of the Ball End handles for the Old Type heads cracked over time, due to a design flaw.

Techs were plentiful, and cheap, and the thread pattern is the same for all Gillette 3 piece razors, so it was very easy for a customer to swap the handles around.

 

[Gray Wolf]

Thanks Gents. All four give me decent shaves, I just didn't know what the silver ones were!