Battery part identification help

[Atavar]

As I stated in another thread I had the battery release knob for one of my batteries fall off on a ride.
Magicycle is singularly unhelpful, saying that lost parts are not a warranty issue. They won’t even tell me where to buy a new part. (Do I look surprised?)
I believe I found a replacement at Biktrix, but they want $20 shipping for a $10 part. Not the end of the world but I thought I would pick the brains of all the wise people at this forum.
Can you look at the pictures below and tell me which manufacturers use a similar battery? I guess (hope) more than one bike maker uses the same batteries.
The pictures are from a 52v 20ah (with knob) and a 52v 15ah (missing knob).
Also, if you could educate me as to what this battery style is called it would make searching easier.

 

[Annieolnie]

I have an idea for you. I have never done this only thought about it, but there are a number of designers on etsy that will 3D print a part for you. You might reach out to this fellow and see if he would be interested. His prices seem quite reasonable, although I don't really know what the initial set up entails. It's an interesting concept.

 

[Atavar]

I received the part from Biktrix in record time and it fits and works perfectly!
Another success story of which I have too few.