The Signode RCD-3431 is used with .75″ high tensile steel strapping. It seals using a double notch, up-cut (reverse notch) seal joint. The RCD-3431 is a little heavier than some sealers, weighing 7 pounds. Signode also makes a 1.25″ steel strapping sealer, the RCD-3431. For easier application, there is a battery powered sealer for steel strapping from Signode, the Grip Pack 114.
Allstrap Opinion: This is a top of the line sealing tool. If you want a less costly tool, try the exact replica of the RCD, the SDN-34.