Looking to replace the Merida post

[nk900]

Hi,
Looking to replace the Merida post, mine is 100mm -
come on eone sixty 900 small.
What its inner /stack /total length?
Also in order to replace it, do I need to disassemble the engine?
Any recommendations on compatible post with 125-150 length ?
Tx

 

[AlexRus]

I install on my 900E (size M) - REVIVE 160 seatpost
REVIVE 160 / 30.9