Wall plate to guide low voltage cabling. You can create your own, customizing many dimensions using this Onshape document. No account is required. The default values are for a single gang version. This is the model that is included in this listing, as Printables requires one. The standard model may require some support material for the fillets on the edges and if you make a custom model the cable chute might as well.

The adjustable parameters (in the upper left of the Onshape page; you may have to scroll or expand this section to see them all) are as follows. They have been ordered from most likely to be changed to least and grouped by feature.

Gang: How many outlet sizes the panel is. One gang is a single outlet's width, two gang is two wide, etc. Default is single gang.

Panel_Horiz_Margin: How much panel border to have horizontally after the outermost screw hole locations. Adjust this to make the panel wider, default is standard size.

Panel_Vert_Margin: How much panel border to have vertically after the outermost screw hole locations. Adjust this to make the panel taller, default is standard size.

Panel_Thick: How thick the walls of the panel are, default is 2 mm.

Panel_Depth: How deep the panel is, to cover the underlying bracket and screws. Default is 3 mm.

Panel_Edge_Rad:  Size of fillet to add the edges of the front of the panel. Default is 2 mm.

Chute_Horiz_Margin: How much border to leave horizontally around the cable chute. Default is 17.5 mm.

Chute_Vert_Margin: How much border to leave vertically around the cable chute. Default is 35 mm.

Chute_Depth: How far the cable chute should extend out from the panel into the wall. Default is 25.4 mm.

Chute_Corner_Rad: What radius to fillet the cable chute inside corners. Default is 15 mm.

Chute_Edge_Rad: What fillet radius to use on the front panel edges of the cable chute. Default is 2 mm, the same as the panel edge radius.

Screw_Hole_D: What diameter hole to create for the screws. The holes are also chamfered for the thickness of the panel. Default diameter is 4 mm.

Screw_Bushing_D: Diameter of the bushing around the screw hole. Default diameter is 10 mm.

Screw_Bushing_Depth: This value adjusts the placement of the panel on top of the outlet box. Default value is 1.5 mm.

Screw_Horiz_Spacing: This is the distance between each gang's screw horizontally. This is a standardized value that really shouldn't need changing. Default is 45.7 mm.

Screw_Vert_Spacing: This is the distance between each gang's screw vertically. This is a standardized value that really shouldn't need changing. Default is 83.3 mm.
 

Really wish Onshape supported custom descriptions or tool tips for these fields…

Once you've set all the parameters, right-click on the model (lower left), choose “export” and select the download format (most people will want “stl”), and finally hit the second “export” button.