Yellow smoke grenade by Black Cat Fireworks.

This smoke grenade produces a thick plume of yellow smoke for approximately 90 seconds.

Yellow Smoke Grenade Specifications
Carton Quantity: 1 x Yellow Smoke Bomb 
Firework Brand: Black Cat Fireworks 
Approx Duration: 90 Sec
Firework Dimensions: 13cm x 4cm
Product Weight: 136g
NEC (Net Explosive Content): 55g
Noise Rating: 0/10
Classification: 1.4G
Firework Category: P1
Safety Distance: 1 Metre - Outdoor Use Only