Pick your own field is an innovative new bet type developed by leading online bookmaker Centrebet. Pick your own field allows the bettor to select a field of runners (2 or more) from within the official field for the race. The bettor must then select who they think will win from their adjusted field. The odds change depending on how many runners the bettor includes in their field.
The selected runner must finish in the top four official placegetters for the race. If no runners from the selected field that finish in the official top four placegetters, the bet will be refunded.
Currently only Centrebet offers this particular bet type. In time more bookmakers may offer a slightly different version of this product.
The example is taken from the Centrebet website. You simply click on the runners you want included in your field and odds update. Then select the runner you think will from the customised field.