CS-Repeater.
A CS-Repeater is when one or more numbers are repeated.

They can be one digit repeaters M 1xxxxxx1 M, two digit repeaters M 12xxxx12 M, three digit repeaters M 321xx321 M, and four digit repeaters M 43214321 M. As long as a sequence repeats itself then it is a repeater. With CS-Repeaters, the numbers in the first set must match the numbers in the second set, M 15xxxx15 M. The CS-2OAKS must be different. If they are CSPairs M 22xxxx22 M, then these are CS-Bookends; if the numbers are mirrored, M 56xxxx65 M, then these are CS-Radars.

CS-Single Bookend Repeater.
CS-Single Bookend Repeater M 1xxxxxx1 M there is an identical number at each end of the FSN.

CS-Tri Bookend Repeater.
CS-Dual Bookend Repeater. CS-Dual Bookend Repeater M 12xxxx12 M the first two digits, which must not match, repeat as the last two digits of the FSN. This is one of the most common repeaters that you will find.

CS-Repeater.
CS-Tri Bookend Repeater M 123xx123 M there are three numbers that repeat. While two of the numbers can match within the first set, all three cannot. The first set starts at position 1, and the second set starts at position 6.

CS-Paired Quad Repeater.
CS-Paired Quad Repeater M 22332233 M the first half is the same as the second half, and the FSN contains four CS-Pairs.

CS-Random Quad Repeater.
CS-Random Quad Repeater M 23012301 M the first four digits match the second four digits.

CS-Triple Repeater.
CS-Triple Repeater M 21021021 M is any three digits that try to repeat itself three times, M 123 123 12 M.

CS-Six Repeater in a Pair.
A CS-Six Repeater in a Pair M 9 301 301 9 M is a CS-Six Repeater inside of a CS-2OAK.

CS-Radar Repeater.
CS-Radar Repeater M 12211221 M is a CS-Quad Repeater that repeats and a CS-Radar that reads right to left the same as left to right, and is also a CS-Full Radar.

CS-Super Repeater.
CS-Super Repeater M 63 63 63 63 M has two different digits repeat four times.

CS-Mini Repeaters.
CS-Mini Repeaters are any sequence of digits that repeat anywhere in the FSN and there are two types: Type 1: The CS-Mini Repeater is grouped M x1212xxx M, in this instance the first digits of the CS-Mini Repeater are repeated by the second set of digits with no space in between. Type 2: Digits in the repeated sequence are separated by one random digit M 1x1xxxxx M or M 12x12xxx M or M x234x234 M.

CS-Mini 3 Repeater.
A CS-Mini Repeater 3 is one CS-2OAK that is separated by one non-similar random digit, M xx1x1xxx M. These are also CS-Mini Radars.

CS-Mini 4 Repeater.
CS-Mini Repeater 4 M x2121xxx M two different digits are repeated and grouped together.

CS-Mini 5 Repeater.
A CS-Mini 5 Repeater is two CS-2OAK’s separated by one non similar random digit M 12x12xxx M.

CS-Mini 6 Repeater.
A CS-Mini 6 Repeater is any three digits that repeat twice and are grouped together, M 12312359 M.

CS-Mini 7 Repeater.
A CS-Mini 7 Repeater is three CS-2OAKs separated by one digit, M 123x123x M.

Note: This page contains excerpts and basic information from the book "The Green Guide to Fancy Serial Numbers". Please consider adding a copy to your library, thank you.