Surfer versions 10 and above are available in both 32-bit and 64-bit versions. Surfer utilizes a hybrid installer, so both the 32-bit version and the 64-bit version are packaged together into a single installer file (EXE or MSI). When you run the installer, the type of operating system you have is automatically detected. If you have a 32-bit operating system, Surfer will automatically install the 32-bit version. If you have a 64-bit operating system, Surfer will default to the 64-bit version, but you do have the option to install the 32-bit version instead if you wish.
Updated August 24, 2020