I know you may have another name for this resource but I call it a paper xylophone.
Mine is made out of a piece of black poster board cut in half and cardstock strips. I don't remember the original length and width of the strips but I do remember that I cut them a 1/4" shorter as I glued each one onto the poster board. I love that my xylophone is laminated because it allows me to easily use a dry erase marker to write on flats/sharps and I can use sticky tack and a white strip of paper to cover any bars that we aren't using.
Today we were working on the second portion of our Teddy Bear lesson. When it came time to play the melody, we discussed how to identify sol/mi on our instruments by first looking at the paper xylophone. I love asking students to come up and demonstrate what we are going to play and I have found that my classes are much more successful when I use this approach.
You can also check out the visual we used during the lesson. While I like this visual, I think I will create another version that includes the rhythmic notation. You can find the visual pictured in the Freebie section.