query: Are there professional airsoft tournaments?
passage: Airsoft
Pellets are usually bought in bags or bottles of 2,000 to 5,000, but other sizes are available, such as a 250,000 round (65kg) package of tournament grade pellets. Biodegradable pellets are a fraction more expensive than non-bio counterparts, but many fields require them. Pellets are typically 6mm in diameter, though 8mm pellets do exist. Pellets vary by diameter depending on the brand (e.g. Matrix pellets are 5.95mm in diameter and let less air slip past it during travel through the barrel, whereas Crosman pellets are 5.93mm in diameter and allow more air to slip past during travel through the barrel and allow for less velocity). Pellets are used for the majority of play, although foam balls may be used to represent M203 grenade launcher shells.[28]
passage: Airsoft
The minimum safe level of gear required to participate in most games includes a pair of ballistic eyewear ANSI Z87.1 (impact-rated) goggles to protect participants' eyes. Traditional prescription glasses and sunglasses, or goggles not designed specifically for use with airsoft or paintball marker, may break or shatter upon being struck, causing injury to the eye. Airsoft guns are not to be confused with BB guns, which fire 4.5 millimetres (0.18in) metal ball bearings.