Technical question about HBT tunic buttons

[Jean-Loup]

Here are two HBT tunic buttons with hooks made of iron, and two with hooks made of aluminum.
I am wondering if there is any reason why some of them have aluminum hooks. Is this a simple variation, or is there logic behind it. For example where the aluminum ones maybe for KM uniforms, so that they would not rust with salt water?

Thanks

JL

[naxos]

The non-ferrous hooks were preferred on white Drillich - since iron ones left visible rust stains after washing.

[Johnny R]

KM tunics as far as I know would also have Anchor buttons. Use of aluminum was reduced during the War and belt ramps etc. made with other metals, the use of both may be related to that or just manufacturing differences as well as what Naxos said which makes sense.