\d{1,3}a digit, repeated between 1 and 3 times
Non-Capturing Group(?:\.\d{3})* *repeats the group contents below any number of times:
\.the literal . (4610 / 568 / 2E16)
\d{3}a digit, repeated exactly 3 times
,the literal , (4410 / 548 / 2C16)
\d{2}a digit, repeated exactly 2 times