A simple timer to keep track of up to 120 seconds saved during time attacks. Mark the arrow opposed to a red one with a finger and rotate to save 1...7 seconds or to spend them on 1...5 dice. Rotate back plate to carry over or remove 30 seconds when passing the 0/1 figures. The name is made up from chronometre and tirelire (piggybank); I do not really speak French, hope it doesn't mean something indecent.
v20120127 allows to spend seconds for 5 dice (instead of 4), and carryover is easier to handle (in the literal sense). You can upgrade the previous version by trimming the corners of the upper square plate a bit back (bigger radius) and cutting the triangles out of the bottom plate (compare old and new, you'll see what I mean).