The North-American Prius 2001 to 2015 came a 12 volt battery with Japanese posts (slightly larger than a pencil). Parts kit for converting the battery to American Style (SAE) Electrical Top Posts (thumb size). This is useful if you want to add a electrical disconnect switch or already have a group 51 battery with American posts you want to install. For the Prius 2001 to 2003 need a 51R battery and we recommend an Optimal as the are a little shorter than most group 51 batteries. For the Prius 2004 to 2015 the 51 size battery is regularly available with Japanese posts it is refereed to as a DS46B24R which is the Japanese battery naming convention. Kit includes: 1 Positive connector with red boot. It attaches to the Toyota + fuse assembly. 2. Negative connector with wire and 6 mm lug to attach to car body. 3. New 6mm bolt with lock washer If you tell us which model (2001-3, 2004-9, 2010-15) we will include instructions with pictures.