The temperature of a heat sealer varies by device. Some are pre-set and some are adjustable. A constant handheld heat sealer for example features an adjustable temperature that can be set anywhere up to 250°C (482°F).
Impulse heat sealers on the other hand are usually measured by time and not temperature, typically though the effective operating temperature will be around 170°C (338°F) depending on the model.
Many band sealers often feature adjustable sealing parameters which includes temperature. Here the temperature is adjustable usually up to 180°C (356°F).
Specialist heat sealers are available with enhanced temperature settings for sealing materials with high heat and pressure tolerances such as FEP film (fluorinated ethylene propylene). Here machines can exceed temperatures of 315°C (599°F).