Burst Smoke, just pull the pin and toss it. That is all there is to it. Burst Smoke Grenades are twin vented, once ignited the composition inside burns very quickly, under 30 seconds. These grenades are not designed to be hand held. As with all pyrotechnics there is a risk of fire. for ages 19+ OUTDOOR USE ONLY. Burn time is approximately 1 minute. ADDITIONAL $45 DANGEROUS GOODS SHIPPING CHARGES APPLY WHEN ORDERING ON LINE. WE DO NOT SHIP TO THE US.