PGSS sign for VACUUM-FLASK

VACUUM-FLASK [Container with insulated wall]
Hold 1st hand as CONTAINER, and put 2nd CUPPED hand, palm upward & fingers forward-inward, with its palm on back of 1st hand; then slide 2nd hand forward-outward-upwards till side of its thumb touches nails of fingers of 1st hand.
[Also for THERMOS]