Old fashioned roman candles were the original aerial color device, and continue to be extremely popular today. Candles, like all consumer fireworks, have a limitation on the amount of composition they can have, which is reflected in the diamter of the candle and the number of shots each contain. A good rule to follow is the "rule of shots" that governs all consumer fireworks. In a nutshell, the more shots, the less power, while the less shots, the more power. This is why 10 shot roman candles are often thinner and less robust than their five and eight shot counterparts.