Nozzle jets are sold individually and made from brass and alum. Jets start at size #20 and go up in increments of 1, if smaller size is needed RBS can sell customer a blank jet and they can drill to size they are after. Largest jet is #130 that can be made from the drop in body.
Nozzle jets are reamed for a smooth bore and consistent flow.
When ordering specify what size and quantity.