What are the differences between the AS-WBXT-201 and AS-WBXT-203 extension cables ?

The AS-WBXT-201 is 500mm (19.7") in length. It can mount from the left side of either a primary ( AS-HDTA-200) or secondary rack ( AS-HDTA-201) to the left side of another secondary rack ( AS-HDTA-201). The secondary rack AS-HDTA-202 can not be used. This cable can be configured with a maximum of 4 racks. Only 1 cable can be used in the configuration.
The AS-WBXT-203 is 700mm (27.5") in length. It mounts from the left side of either a primary ( AS-HDTA-200) or secondary rack ( AS-HDTA-201) to the right side of another secondary rack ( AS-HDTA-201). The secondary rack AS-HDTA-202 can not be used. This cable allows the last receptacle to be free for use of the Gas Flow Enabler Key to be used. It also limits the maximum rack configuration to 3 racks. Only 1 cable can be used in the configuration.