If you own a newer BMW, you know the convenience of being able to check your oil level on the dash - if you're searching for this part, you also probably know that they can be finicky.
Why didn't BMW just put a dipstick in? We're not sure either. This Genuine BMW oil level sensor bolts into the drain pan and includes the sealing gasket! 
 
Previous Revisions
12-61-7-567-723, 12 61 7 567 723, 12.61.7.567.723, 12617567723
12-61-7-506-689, 12 61 7 506 689, 12.61.7.506.689, 12617506689
12-61-7-540-351, 12 61 7 540 351, 12.61.7.540.351, 12617540351
12-61-7-549-805, 12 61 7 549 805, 12.61.7.549.805, 12617549805
Cross Reference
12617607910, 12-61-7-607-910, 12 61 7 607 910, 12.61.7.607.910
12617607910, 12-61-7-607-910, 12 61 7 607 910, 12.61.7.607.910
12610400034, 12-61-0-400-034, 12 61 0 400 034, 12.61.0.400.034
12610412430, 12-61-0-412-430, 12 61 0 412 430, 12.61.0.412.430
12610422012, 12-61-0-422-012, 12 61 0 422 012, 12.61.0.422.012
12617567723, 12-61-7-567-723, 12 61 7 567 723, 12.61.7.567.723
12610148464, 12-61-0-148-464, 12 61 0 148 464, 12.61.0.148.464