Stainless Sig 239 prismatic finish question

[CRShooter32]

I found a neat looking Sig 239, .40 cal., last weekend, and have a question as to what type of finish this is. It was used, and didn't have the box, or manual with it.

It's two tone, but the slide has a rainbow/prismatic style finish to it. Depending on the angle, the top of the slide chages from a dark green to a dark purple color, so it does not reflect the light, and give off any glare.

Sig's website didn't have any information about this model having a finish like this.

[StarPD]

Probably a custom, maybe home brewed finish put on by previous owner.

[rotty]

this is anodized i believe, it was a special run by SIG on only the 239's, I have ordered a couple from sig, customer request.:sad: