SD are Volks' first range of SD type dolls released. They are meant to represent children of around 10 years of age and so are sometimes referred to as SD10, but Volks refers to them as "standard" to differentiate from SD13. They are roughly 55-56cm (22inches) tall, and have approximately a 22-25cm (8.7-9.8inches) sized head. Most of them can also wear DD sized wigs, but the older models who have larger heads will find them a tight fit. SD are the same size as the Tenshi type KyoTenshi.