With 32 cars at Grindelwald there was an amazing variety of customisation - here's the variety of air filters, and I'm not sure I photographed them all - got a different one? Add it to the thread.

Attached Images
_DSC3396.jpeg (32.22 KB, 691 downloads)
IMG_7786.jpeg (31.28 KB, 694 downloads)
IMG_7842.jpeg (37.61 KB, 697 downloads)
IMG_7843.jpeg (37.46 KB, 698 downloads)
IMG_7844.jpeg (36.88 KB, 693 downloads)
Omne trium perfectum