Where do you find the metal coat in soul silver?

You can't find the Metal Coat in Soul Silver! It's a trade evolution item used to evolve Onix into Steelix.

Here's how you can get it:

* Trade: The Metal Coat is most commonly obtained through trading with another player.

* Events: There are occasional events where you can get Metal Coats, but they are rare.

Important Note: Soul Silver is an older game and doesn't have online trading like newer games. You'll need to find someone with a copy of Soul Silver and a spare Metal Coat to trade with.