The Collet fits Merry Tools Routers and 3612B ,3612BR Makita Routers and other type of Makita brand Routers . Two sizes are available in our shop which are From 12mm to 6 & 8mm, From 1/2" to 1/4" and 3/8". But please note that the price here is for 12mm to 6mm and 8mm which is for 12mm shank router bits.