Grohe - o-Ring holder - item 12701000

The bath/shower regulation started dripping. Opening the "mixer" revealed the problem: one of the o-ring holders (a small metal ring inside a rocket booster looking part) was broken.
Replacement item: 55Euro (excl VAT) + 4wks leadtime. : (
Replaced it with an ABS ring. Estimate price 0.5Euro, lead-time ±4minutes.