Graven Games posted up a review of Forge World brass etchings for Crimson/Imperial Fists.
From the review:
Today we take a look at the Forge World etched brass detailing kit for Crimson/Imperial Fists space marines. The etched brass series are some of the few products produced by Forge World that are not made in resin, and is a nice alternative to sculpted details or transfers which are also available in several varieties from their range of kits. It is important to notice that etched brass can be extremely sharp and should be handled with care.