Split Shot.

Used to weight your float so that it sits right in the water, Split Shot is available is a multitude of sizes. The size of the shot is given by either a number or some letters. This will probably look like gibberish until you start using it and learn your 'Shotting Conversion Table'. The bigger the number, the smaller the shot. The shot with letters are the bigger sizes.
It is important to remember that shot of size 8 and smaller, are still made from lead. Always use a set of pinchers or a specially made tool to fix shots to your line. 

Shotting Conversion Table <click