Thermochromism - heat-sensitive paint logo.

8cm diameter.

9.5cm tall.

One is made by Zak Designs - all black with the Batman logo and skyline which changes colour when filled with boiling water (see images). No longer available from Zak's American website.

The other has no brand markings but is similar.

Black outside, white inside.

It has 2 Batman logos which change colour when filled with boiling water (see images).

SELLING THE 2 TOGETHER.