Hello Sentry is a product made by uAvionix (manufacturer of the SkyEcho) and the product is more or less exactly the same but ordered by ForeFlight to be the companion of this EFB in US.
We tested the compatibility with SkyEcho / SafeSky / ForeFlight, and it’s working fine.
Concerning the Sentry, we are not equipped with this device and we couldn’t give you an answer.
Anyway I suggest that you test it with the same config of the SkyEcho2.
But I confirm that you can add SafeSky Traffic with the SkyEcho2 traffic and share all traffics with ForeFlight.
Keep us posted with your experience with the Sentry, we will share this conclusion with the community of SafeSky pilots.
Don’t hesitate to read our user manual, and videos (YouTube).