Why do flight attendants have to pull a box when they get on and off the plane? What's in it?

According to flight attendant Cloe Chen, her suitcase contains these:

CCOM (crew operation manual? (that is, the meaning of the operation manual)

A pair of flat shoes

A spare pair of new socks.

parking apron

Lip protection honey

lipstick

The novel is locked.

hand cream

Salt and pepper (and all kinds of spices)

gloves

acrylic foam tape

pen

perfume

vacuum bottle

Medicine (stomach medicine, cold medicine)

Good stretch

A suit of casual clothes

That's about it.