According to SAF Dress Manual....
LTC and below, SAF crest.
COL... that Crest with laurels.
BG and above, pineapple. its a sword and baton symbol with
Singapore coat of arms on it.
On CDF... because he is representing the 3 services... he wears the
Joint staff crest... if you look closely it resembles UK's Crest.
It has a Sword (Army), Wings (Air Force), and Anchor (Navy). The
difference between singapore and UK is that UK is topped by a crown
whereas singapore on is by Coat of Arms.