1/4 inch time fuse is commonly used inside fireworks shells to give a reliable, timed source of ignition to the inside of the firework shell. This allows the shell to burst right at apogee.
Time fuse is relatively difficult to light and should always be cross-matched to maximize the chances of ignition. You can use GN1010 Cross-Match Visco, or harvest black match from either Quickmatch or GN1205 Superfast Paper Fuse.
This high quality, Chinese made, time fuse burns at about 3 seconds per inch and works well for 7/32" size fuse holes.