The Garmin holder is designed to stand on the dashboard.
I made it because
1) The suction cup was not too good
2) I would like to have the more central place but without it covering the window.
I have made the model for the Garmin nüvi® 2547 but it looks like all models in the nüvi® 25XX group will fit the holder.
To prevent it from sliding back and forth, I've put it on an anti slip pad.
Garmin nüvi® 2547 Physical dimensions: W: 13.7 x D: 1.9 x H: 8.3 cm
PS. the sides are extended up by 5mm in relation to the holder on the photo, even that the holder fits nicely, is there is / was a little rocking back and forth. Hope it will help.
any brand ABS / ASA