This is a "strap keeper" replacement. I copied measurements from the one I broke after a year.

Consider this abandoned because it turns out the entire strap is compromised (after I had already designed & printed this part).

In the future I would thin it out some (this is Rev 2 - untested) because the TPU filament I used (95A hardness, I think) is decently harder than the silicone the stock Garmin piece is.

However, it is indeed still functional.