Built-in browser push notification service gives you the ability to send notifications to users who visited your product listing.
The Productific dashboard indicates the audience than can be reached with a push message:
When new ideas are up for voting or planned features become available Productific can notify your audience about this. The dashboard will show some key statistics about push messages in the outbound section so you are aware of audience size as well as delivered/received/opened messages.
Productific's Business plan provides custom messages, you can send any message to your browser audience. For good user engagement make sure your messages are relevant and with good content, be careful not to spam your visitors.