2 Pcs Adjustable Desk Wall Spacers - Table Wall Protectors, Desk Top Spacers, Wall Bumpers, Furniture Protectors (White)

I have a much sturdier looking desk, but even it would wiggle slightly when I used my mouse and keyboard. With monitor arms, if your desk isn't completely stationary, you'll get a lot of wiggling. I got some adjustable desk wall spacers that attach to the back of the desk and press up against the wall. This fixed it completely, zero wiggle. There are some that attach via adhesive, they are worthless and will eventually fall off.