I had a request for a … call it ‘covert’ status indicator. Needed to be fairly small, about 1.5x3", but thin. So I targeted 40x80mm and managed to get it down to only 2.2mm thick!

Once printed, use a fine-point applicator and apply a thin line of CA glue along the bottom edge of the red/green parts, all the way around the perimeter. Don't over-do the glue or it'll get in the slider channel!

Place the slider in between the parts and press it together. The little notches will help make sure everything is lined up. Secure it to wherever you need with some VHB tape and you're done.

PS: Use an opaque material. There's only three layers of color here, so if you use something translucent (particularly against a dark background) it'll become very muted. PLA matte or PETG are good choices - I used BBL PETG-HF and not only are the colors still fairly vibrant but it's silent. PLA has a tendency to be noisy when scraped together.