Summary

http://goo.gl/4RvauY

Based on the orignal idea - a headset hook for Ikea LINNMON tabletop ( thickness : 34 mm ), this version add 2 mm space to fill in a "non-slip mat".

Here offers several different size for tables ( thickness : 18 / 20 / 34 / 36 mm ), and 2 different length ( 35 / 50 mm ) .
This model can be customized as well - just left a comment.

Printing Profile :
infill : 30%
shells : 2
layer height : 0.2 mm
raft : no
support : no
material use : around 19 g
Print time : around 100 minutes

original design
http://www.thingiverse.com/thing:239887
non-slip mat @ ebay
http://www.ebay.com/bhp/non-slip-mat