My Steelseries Apex keyboard recently lost one of its rear feet during a move, and Steelseries support doesn't sell or provide replacements. This is a model for a replacement foot that roughly matches the stock foot – it's not an exact reproduction, but the external dimensions are the same to within 1/32" and the replacement fits snugly in the existing slot without excess force.

I believe this foot is compatible with any Steelseries Apex keyboard, including the Apex 3 and 3 TKL, the Apex 5, the Apex 7 and 7 TKL, the Apex 9 TKL and 9 mini, and the Apex Pro. (Please let me know if it isn't!)

Any rigid material is fine. ABS, PETG and PLA+ are ideal, but I used plain PLA and the arms still comfortably bent enough to fit the pegs in. The pegs need some minimal supports, and I recommend a very small layer thickness to smooth out the sloped top surface.

The stock feet have a slightly rubberized surface on the tips. If this is something you need, dip the feet in Plastikote or a similar tacky surface preparation.