FAA-PMA
AT420100 is an FAA-PMA part by Ads/Transcoil
PMA PQ2107NE. Approved as a replacement for 548-516 on Piper PA31-T, PA31-T1, PA31-T3, PA31P-350, PA42-720, PA42-1000 (Clock) · Current, May 2010. · in stock here Leading Edge Group, LLC, quote
The OEM number it replaces, and who sells those here
- 548516no listing here yet
A PMA part is approved for the specific eligibility listed on its FAA record; whether it may be installed on a particular aircraft, engine or component is the installer's determination. This page states the FAA record and the listings on PartsAndPlanes.