A voice type is a particular kind of human singing voice perceived as having certain identifying qualities or characteristics. Voice classification is the process by which human voices are evaluated and are thereby designated into voice types. These qualities include but are not limited to: vocal range, vocal weight, vocal tessitura, vocaltimbre, and vocal transition points such as breaks and lifts within the voice. Other considerations are physical characteristics, speech level, scientific testing, and vocal registration.[1] The science behind voice classification developed within European classical music and is not generally applicable to other forms of singing. Voice classification is often used within opera to associate possible roles with potential voices.