Customized version of http://www.thingiverse.com/thing:351541

Created with Customizer! http://www.thingiverse.com/apps/customizer/run?thing_id=351541

Using the following options:

side_slit_periodic_length = 4
head_diameter = 82
head_cylinder_height = 3
side_slit_opening_ratio = 0.5
main_cylinder_height = 15
side_slit_top_margin = 2.4
gradient_height = 3
side_slit_bottom_margin = 1.2
inner_diamter = 75
filter_opening_ratio = 0.5
filter_periodic_length = 4
filter_height = 2
outer_diameter = 78
filter_beam_aspect_ratio = 2