Bosch Lock Ring Tool, for Mounting the Locking Ring, Black, One Size

Wrong size, does not fit cx 2020 generation 4 motor

Really this should not be more than £10, and it's a required tool with how quickly bosch powered bikes go through chains (and you need to change the ring when you change chain of you get horrible chainsuck).

OK, I know it’s a genuine BOSCH part but this is really expensive for something you will ever use occasionally. Quality is as you would expect but really.....

could do with a nut on the facing so you can use an adjustable spanner. You could then put an axle shaft through the bottom bracket with a couple of nuts and large washers either side, to hold it in place while you undo the chainring guard, otherwise it keeps slipping off the chainring nut and damages the chainguard