This is the replacement hose running from the auxiliary water pump to the auxiliary cooling radiator on M Sport F30 335i and F32 435i (and the M235i/M240i Racing). Only M Sport models came equipped with this hose and radiator located in the driver side wheel well. This hose has rubber and metal sections with many connectors in between that are prime sources for a coolant leak.
This is a Genuine BMW radiator hose with a two year warranty. Buying a Genuine part will usually be more expensive than an OEM or aftermarket brand but you are assured that it meets BMW's designs for fitment, performance, and longevity. It will also be the very latest design, incorporating any updates or revisions that an aftermarket brand typically will ignore.
F22 / F23 (2014-2021) > M235i-Racing
F22 / F23 (2014-2021) > M240i-Racing
F30 / F31 / F34 (2012-2019) > 335i
F30 / F31 / F34 (2012-2019) > 335i xDrive
F32 / F33 / F36 (14-20) > 435i
F32 / F33 / F36 (14-20) > 435i xDrive