This tube holder is designed to be nailed into position, securing tubes or hoses of nominally 6.5mm Outer Diameter. The actual internal diameter of the clip section is 6.8mm, to allow for printing tolerances. The offset toggle will apply pressure to the hose as the clip is nailed/screwed into position, allowing it to be used with 6mm - 6.8mm hoses while still applying pressure. The screw hole is 1.5mm diameter, suitable for small nails and screws.Print as many as you need to hold up small tubes, etc. Mount using a 1 - 1.5mm nail or small diameter screw. The offset toggle means that pressure is applied to the hose when you nail it in position, making up for undersize tubes, etc not being gripped firmly by the clip. When printing this, I found that if my extrusion widths were two high, I ended up with a thin walled object, as it couldn't fit enough perimeters in, and the infill wasn't high enough to join the surfaces (see comments here: http://teslaandi.wordpress.com/2013/12/30/thin-profile-printing/ )