The Fat Boy Jet Kit is designed exclusively to fine-tune the main jetting on the Mercury 2.4 Liter WH carburetor and 2.5 Liter WMV series carbs running on a cross-drill reed plate. 
 
The Fat Boy Kit, the first to offer single number jet size increments (vs mercury double jumps), includes: 2 x 91, 2 x 92, 2 x 93, 2 x 94, 2 x 95, 2 x 96, 2 x 97, 2 x 98, 2 x 99, 2 x 100s! 18 main jets in total! 

Each jet is precision machined and is laser size-marked on the side of the barrel.