Liquid Timers Double - 3 Colours - One Supplied offers a thoughtfully designed, durable resource for hands-on learning. You simply turn them upside down and watch the two differently coloured bubbles simultaneously flow to the bottom of the tube. The liquid timer takes approx. 1 min to run through. Please note these timers are for sensory calming and not for accurate time management. The action of the liquid showers can stimulate visual learning with regards to colours and the passing of time. This sensory activity is praised as fun and stimulating. * Colours may vary Features: Captivating liquid timer Popular sensory aid Entrancing colours & flow Use to teach colours & the concept of time Size9 x 3 x 14 cm Usage: Visual effects Material: Plastic/Glass Weight: Approx.: 220 g.