Plumes of silver sparks of varying height and duration, shoot up to create a glittering effect.
 
The first number shows the burn time (in seconds) and the second number shows the height (in feet). The height is defined as the top of the main plume, some sparks will go higher. For example: a 1/4 x 20 is a jet of 1/4 of a second duration that reaches a height of 20ft.
 
Jets are also sometimes referred to as short duration gerbs.
 
PP436 1 x 50 Jet is a category T2 product, intended for use only by persons with specialist knowledge.