Derby Extra mystery blade

[Roman Totale XVII]

I’m using up some part tucks that I have and last night reached for a white plastic tuck of Derby Extras. I noticed that the blade I slid out was in unbranded wax paper, unlike the others, also the blade had rounded corners that I didn’t recall seeing before on that blade. It’s been at least a year since I last used a Derby Extra though, so didn’t think anything about it.
Reached for the razor this morning, swiped my face and nothing whatsoever. Tried a few more times and all that was happening was soap removal. I grabbed my other DE in rotation and finished the shave.
Took out the blade and compared it to the next Derby Extra in the tuck, a ‘normal’ looking one and lo and behold, this other blade is noticeably smaller. What is it???

 

[Pinto90]

I would venture that the blade on the right is a very special type perhaps sold for the Turkish market or an old model from many years ago that is no longer in use.
Out of curiosity could you show the package where you got this blade?

 

[Frito Ray]

Out of curiosity could you show the package where you got this blade?

And where you got it too please.

 

[Roman Totale XVII]

^ ^^
It’s just the regular packaging. Not my pic, but looks just like the below.
As to where I got it, I don’t recall at all. I’d ordered some sample mix packs from a couple of places. Maggards is the most likely, but it could have been Razor Emporium.

 

[Pinto90]

@Roman Totale XVII To be clear, did you receive the razor blade that is on the right in your photo in a regular Derby Extra package like the one in the photo?

Maybe I didn't understand the point of your previous opening message, so I'm asking you.
Did you find these two razor blades in the same package?
A regular packaging of Derby Extra blades?

 

[Roman Totale XVII]

^ Yes. That’s precisely what has happened. This blade was randomly in the middle of a tuck of otherwise regular Derby Extra blades.

 

[Frito Ray]

Wierd…I do like the rounded tabs though.

 

[Pinto90]

@Roman Totale XVII Really strange what happened to you, however despite everything the Mysterious Derby blade is very characteristic and curiosity to use.

 

[Frito Ray]

Possibly Derby uses the same box filling machine for all their blades and one just got stuck from another production line.

You got an extra Extra.

 

[Salty_Shaver]

Looks like a blank that got over machined and incomplete and passed through QC. Kinda like an oil filter I bought that had an unfinished base plate with no center hole to spin it on. It happens.