Flir Systems Inc. has announced a $425 million note offering of 3.125 percent, due June 15. Flir expects to receive net proceeds of $421 million after deducting underwriting discounts and estimated offering expenses. The proceeds from the note sale are expected to be used to prepay existing $250 million principal amount notes due Sept. 1 and for general corporate purposes. The offering is expected to close on June 10. Flir designs and manufactures sensor systems and components used for thermal imaging, situational awareness and security applications.