The 1.0 version of Pigtail-S for Mac was available to download on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. This program's bundle is identified as net.pignology.Pigtail-S. The most popular version of Pigtail-S for Mac is 1.0. The software relates to System Tools. This Mac application is a product of Pignology, LLC. We recommend checking the downloaded files with any free antivirus.
From the developer:
Pigtail-S emulates the functionality of the Pigtail hardware device made by Pignology, LLC. It provides a bridge between the app HamLog on iOS devices and Mac and amateur radios.This app requires an attached serial to USB adapter connected to an amateur radio to function.
You may want to check out more software for Mac, such as toDoo, NWD-211AN Utility or BESAgent, which might be similar to Pigtail-S.