Customized version of http://www.thingiverse.com/thing:251470

Created with Customizer! http://www.thingiverse.com/apps/customizer/run?thing_id=251470

Using the following options:

arm_depth = 4
arm_width = 8
guide_y = 35
guide_x = 45
filament_guide_wall_width = 3
grip_opening_height = 20
frame_thickness = 5
grip_wall_thickness = 4
side = 0
filament_guide_depth = 4
grip_depth = 18
filament_guide_notch_width = 2
inner_diameter = 15