Tamron - Pentax 15-30mm 2.8 150mm Filter adapter

EDIT 6/618 -
Added Filter mount V2 - shaved 2mm off the original mount to bring the filter down closer to the front of the lens and reduce possibility of vignetting.
Added Double filter mount - for mounting two filters simultaneously without the need for printing a second squat mount, this also makes it more compact and reduces vignetting.
Added Outer ring 10mm inserts - Holes for the threaded inserts are deeper to allow M4x6x10mm brass threaded inserts, making it easier to find a screw of s