Hi @ASNeelima,
If you keep value 2 on deduplication and let's say for example you're using identification based on email then it will output maximum of two records if it finds same email address two or three etc. more times in ACS. If it finds only one email address then it will output that as well.
Another example, i have cart browsing activity which stores multiple entries on email address + product id in ACS. If i want to pass only recent two products browsed then i can use deduplication activity set to output 2 unique records.
Thanks!
Thanks, Sathees