Hot Wheels Twin Mill Lunch Box. A vintage 1998 gold tint metal Hot Wheels lunch box Thermos featuring the “Twin Mill”. The Twin Mill with two motors debuted in 1969. It was such a popular model that Hot Wheels made a fully functioning full scale replica of it which appears at car shows. This collectible Hot Wheels Twin Mill Lunch Box was never used. The thermos is not included. It is in very good condition.